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1.
Circ Res ; 2024 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-39465245

RESUMO

BACKGROUND: Given the growing acknowledgment of the detrimental effects of excessive myocardial fibrosis on pathological remodeling after myocardial ischemia-reperfusion injury (I/R), targeting the modulation of myocardial fibrosis may offer protective and therapeutic advantages. However, effective clinical interventions and therapies that target myocardial fibrosis remain limited. As a promising chimeric antigen receptor (CAR) cell therapy, whether CAR macrophages (CAR-Ms) can be used to treat I/R remains unclear. METHODS: The expression of FAP (fibroblast activation protein) was studied in mouse hearts after I/R. FAP CAR-Ms were generated to target FAP-expressing cardiac fibroblasts in mouse hearts after I/R. The phagocytosis activity of FAP CAR-Ms was tested in vitro. The efficacy and safety of FAP CAR-Ms in treating I/R were evaluated in vivo. RESULTS: FAP was significantly upregulated in activated cardiac fibroblasts as early as 3 days after I/R. Upon demonstrating their ability to engulf FAP-overexpressing fibroblasts, we intravenously administered FAP CAR-Ms to mice at 3 days after I/R and found that FAP CAR-Ms significantly improved cardiac function and reduced myocardial fibrosis in mice after I/R. No toxicities associated with FAP CAR-Ms were detected in the heart or other organs at 2 weeks after I/R. Finally, we found that FAP CAR-Ms conferred long-term cardioprotection against I/R. CONCLUSIONS: Our proof-of-concept study demonstrates the therapeutic potential of FAP CAR-Ms in alleviating myocardial I/R and potentially opens new avenues for the treatment of a range of heart diseases that include a fibrotic phenotype.

2.
J Neurosci ; 44(26)2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38664013

RESUMO

The periaqueductal gray (PAG) is a small midbrain structure that surrounds the cerebral aqueduct, regulates brain-body communication, and is often studied for its role in "fight-or-flight" and "freezing" responses to threat. We used ultra-high-field 7 T fMRI to resolve the PAG in humans and distinguish it from the cerebral aqueduct, examining its in vivo function during a working memory task (N = 87). Both mild and moderate cognitive demands elicited spatially similar patterns of whole-brain blood oxygenation level-dependent (BOLD) response, and moderate cognitive demand elicited widespread BOLD increases above baseline in the brainstem. Notably, these brainstem increases were not significantly greater than those in the mild demand condition, suggesting that a subthreshold brainstem BOLD increase occurred for mild cognitive demand as well. Subject-specific masks were group aligned to examine PAG response. In PAG, both mild and moderate demands elicited a well-defined response in ventrolateral PAG, a region thought to be functionally related to anticipated painful threat in humans and nonhuman animals-yet, the present task posed only the most minimal (if any) "threat," with the cognitive tasks used being approximately as challenging as remembering a phone number. These findings suggest that the PAG may play a more general role in visceromotor regulation, even in the absence of threat.


Assuntos
Imageamento por Ressonância Magnética , Memória de Curto Prazo , Substância Cinzenta Periaquedutal , Humanos , Substância Cinzenta Periaquedutal/fisiologia , Masculino , Feminino , Memória de Curto Prazo/fisiologia , Adulto , Imageamento por Ressonância Magnética/métodos , Adulto Jovem , Mapeamento Encefálico
3.
Nano Lett ; 24(23): 7055-7062, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38810105

RESUMO

Transparent passive cooling materials can cool targets environmentally without interfering with light transmission or visual information reception. They play a prominent role in solar cells and flexible display cooling. However, achieving potent transparent cooling remains challenging, because light transmission is accompanied by thermal energy. Here we propose to realize effective passive cooling in transparent materials via a microscale phase separation hydrogel film. The poly(N-isopropylacrylamide-co-acrylamide) hydrogel presents light transmittance of >96% and infrared emissivity as high as 95%. The microphase-separated structure affords a higher enthalpy of evaporation. The film is highly adhesive. In field applications, it reduces temperatures by 9.14 °C compared to those with uncovered photovoltaic panels and 7.68 °C compared to those for bare flexible light-emitting diode screens. Simulations indicate that energy savings of 32.76-51.65 MJ m-2 year-1 can be achieved in typical tropical monsoon climates and temperate continental climates. We expect this work to contribute to energy-efficient materials and a carbon-neutral society.

4.
Mol Psychiatry ; 28(6): 2540-2548, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36991135

RESUMO

Adolescents experience alarmingly high rates of major depressive disorder (MDD), however, gold-standard treatments are only effective for ~50% of youth. Accordingly, there is a critical need to develop novel interventions, particularly ones that target neural mechanisms believed to potentiate depressive symptoms. Directly addressing this gap, we developed mindfulness-based fMRI neurofeedback (mbNF) for adolescents that aims to reduce default mode network (DMN) hyperconnectivity, which has been implicated in the onset and maintenance of MDD. In this proof-of-concept study, adolescents (n = 9) with a lifetime history of depression and/or anxiety were administered clinical interviews and self-report questionnaires, and each participant's DMN and central executive network (CEN) were personalized using a resting state fMRI localizer. After the localizer scan, adolescents completed a brief mindfulness training followed by a mbNF session in the scanner wherein they were instructed to volitionally reduce DMN relative to CEN activation by practicing mindfulness meditation. Several promising findings emerged. First, mbNF successfully engaged the target brain state during neurofeedback; participants spent more time in the target state with DMN activation lower than CEN activation. Second, in each of the nine adolescents, mbNF led to significantly reduced within-DMN connectivity, which correlated with post-mbNF increases in state mindfulness. Last, a reduction of within-DMN connectivity mediated the association between better mbNF performance and increased state mindfulness. These findings demonstrate that personalized mbNF can effectively and non-invasively modulate the intrinsic networks associated with the emergence and persistence of depressive symptoms during adolescence.


Assuntos
Transtorno Depressivo Maior , Atenção Plena , Neurorretroalimentação , Humanos , Adolescente , Transtorno Depressivo Maior/terapia , Projetos Piloto , Imageamento por Ressonância Magnética , Rede de Modo Padrão , Encéfalo/fisiologia , Mapeamento Encefálico , Vias Neurais/fisiologia
5.
Bioorg Chem ; 151: 107675, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39126868

RESUMO

Rho-associated coiled-coil kinase (ROCK) is involved in multiple cellular activities regulating the actin cytoskeleton, such as cell morphology, adhesion, and migration. The inhibition of ROCK is a feasible strategy to suppress breast cancer metastasis. Herein, based on Belumosudil, a series of pyrazolo[1,5-a]pyrimidine derivatives as selective ROCK2 inhibitors were designed and synthesized. Through systematic investigation of SARs, the piperazine analog 7u was identified with optimum ROCK2 inhibitory activity (IC50 = 36.8 nM) and excellent selectivity over the isoform protein ROCK1 (>250-fold). Intriguingly, upon treatment with 7u, the arrangement of the MDA-MB-231 cytoskeleton was affected accompanied by the alteration of morphology. Furthermore, cell scratch and transwell assays indicated that 7u inhibited MDA-MB-231 cell migration and invasion in a dose-dependent manner. Ultimately, the binding model of 7u with ROCK2 well accounted for the superior activities of 7u as a promising ROCK2 inhibitor with the potential application in breast cancer metastasis treatment.


Assuntos
Antineoplásicos , Neoplasias da Mama , Movimento Celular , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores de Proteínas Quinases , Pirazóis , Pirimidinas , Quinases Associadas a rho , Humanos , Quinases Associadas a rho/antagonistas & inibidores , Quinases Associadas a rho/metabolismo , Movimento Celular/efeitos dos fármacos , Pirimidinas/farmacologia , Pirimidinas/química , Pirimidinas/síntese química , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/síntese química , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Relação Estrutura-Atividade , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Feminino , Pirazóis/farmacologia , Pirazóis/química , Pirazóis/síntese química , Estrutura Molecular , Proliferação de Células/efeitos dos fármacos , Linhagem Celular Tumoral , Descoberta de Drogas , Simulação de Acoplamento Molecular
6.
Cereb Cortex ; 33(10): 6028-6037, 2023 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-36520501

RESUMO

Recollection of past events has been associated with the core recollection network comprising the posterior medial temporal lobe and parietal regions, as well as the medial prefrontal cortex (mPFC). The development of the brain basis for recollection is understudied. In a sample of adults (n = 22; 18-25 years) and children (n = 23; 9-13 years), the present study aimed to address this knowledge gap using a cued recall paradigm, known to elicit recollection experience. Successful recall was associated with activations in regions of the core recollection network and frontoparietal network. Adults exhibited greater successful recall activations compared with children in the precuneus and right angular gyrus. In contrast, similar levels of successful recall activations were observed in both age groups in the mPFC. Group differences were also seen in the hippocampus and lateral frontal regions. These findings suggest that the engagement of the mPFC in episodic retrieval may be relatively early maturing, whereas the contribution to episodic retrieval of more posterior regions such as the precuneus and angular gyrus undergoes more protracted maturation.


Assuntos
Mapeamento Encefálico , Imageamento por Ressonância Magnética , Adulto , Criança , Humanos , Rememoração Mental , Encéfalo/diagnóstico por imagem , Lobo Parietal
7.
Neuroimage ; 268: 119879, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36642154

RESUMO

Thirty years of neuroimaging reveal the set of brain regions consistently associated with pleasant and unpleasant affect in humans-or the neural reference space for valence. Yet some of humans' most potent affective states occur in the context of other humans. Prior work has yet to differentiate how the neural reference space for valence varies as a product of the sociality of affective stimuli. To address this question, we meta-analyzed across 614 social and non-social affective neuroimaging contrasts, summarizing the brain regions that are consistently activated for social and non-social affective information. We demonstrate that across the literature, social and non-social affective stimuli yield overlapping activations within regions associated with visceromotor control, including the amygdala, hypothalamus, anterior cingulate cortex and insula. However, we find that social processing differs from non-social affective processing in that it involves additional cortical activations in the medial prefrontal and posterior cingulum that have been associated with mentalizing and prediction. A Bayesian classifier was able to differentiate unpleasant from pleasant affect, but not social from non-social affective states. Moreover, it was not able to classify unpleasantness from pleasantness at the highest levels of sociality. These findings suggest that highly social scenarios may be equally salient to humans, regardless of their valence.


Assuntos
Mapeamento Encefálico , Encéfalo , Humanos , Teorema de Bayes , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem , Emoções , Comportamento Social , Imageamento por Ressonância Magnética/métodos
8.
Opt Lett ; 48(22): 5935-5938, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37966756

RESUMO

We present the design and fabrication of an on-chip FBG interrogator based on arrayed waveguide grating (AWG) technology. The spectral overlap between adjacent channels in the integrated AWG is significantly enhanced through a combination approach involving the reduction of the output waveguide spacing and an increase in the input waveguide width. As a result of these design choices, our AWG demonstrates excellent spectral consistency, with spectral cross talk exceeding 30 dB. The interrogator seamlessly combining optical and circuitry components achieves full integration and enables a wide range of interrogation wavelengths, including C-band and L-band. With an interrogation range extending up to 80 nm, it theoretically has the capacity to simultaneously interrogate the wavelengths of 20 FBG sensors. Experimental findings demonstrate an absolute interrogation accuracy of less than 2 pm for the fully integrated interrogator. With its compact size, cost-effectiveness, exceptional precision, and ease of integration, the proposed interrogator holds a substantial promise for widespread application in the realm of FBG sensing.

9.
BMC Psychiatry ; 23(1): 757, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37848857

RESUMO

BACKGROUND: Adolescence is characterized by a heightened vulnerability for Major Depressive Disorder (MDD) onset, and currently, treatments are only effective for roughly half of adolescents with MDD. Accordingly, novel interventions are urgently needed. This study aims to establish mindfulness-based real-time fMRI neurofeedback (mbNF) as a non-invasive approach to downregulate the default mode network (DMN) in order to decrease ruminatory processes and depressive symptoms. METHODS: Adolescents (N = 90) with a current diagnosis of MDD ages 13-18-years-old will be randomized in a parallel group, two-arm, superiority trial to receive either 15 or 30 min of mbNF with a 1:1 allocation ratio. Real-time neurofeedback based on activation of the frontoparietal network (FPN) relative to the DMN will be displayed to participants via the movement of a ball on a computer screen while participants practice mindfulness in the scanner. We hypothesize that within-DMN (medial prefrontal cortex [mPFC] with posterior cingulate cortex [PCC]) functional connectivity will be reduced following mbNF (Aim 1: Target Engagement). Additionally, we hypothesize that participants in the 30-min mbNF condition will show greater reductions in within-DMN functional connectivity (Aim 2: Dosing Impact on Target Engagement). Aim 1 will analyze data from all participants as a single-group, and Aim 2 will leverage the randomized assignment to analyze data as a parallel-group trial. Secondary analyses will probe changes in depressive symptoms and rumination. DISCUSSION: Results of this study will determine whether mbNF reduces functional connectivity within the DMN among adolescents with MDD, and critically, will identify the optimal dosing with respect to DMN modulation as well as reduction in depressive symptoms and rumination. TRIAL REGISTRATION: This study has been registered with clinicaltrials.gov, most recently updated on July 6, 2023 (trial identifier: NCT05617495).


Assuntos
Transtorno Depressivo Maior , Atenção Plena , Neurorretroalimentação , Humanos , Adolescente , Transtorno Depressivo Maior/diagnóstico por imagem , Transtorno Depressivo Maior/terapia , Imageamento por Ressonância Magnética/métodos , Neurorretroalimentação/métodos , Giro do Cíngulo/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos
10.
Toxicol Appl Pharmacol ; 444: 116020, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35430233

RESUMO

Titanium dioxide often enters the respiratory tract in the form of nano-dust in occupational sites. Metabolomics may be a promising method for studying the toxicology of nano titanium dioxide. The intention of this study was to explore the possible impact of titanium dioxide nanoparticles (TiO2 NPs) on the metabolomics signatures of human normal bronchial epithelial (BEAS-2B) cells and to search for investigate the role of reactive oxygen species (ROS). In this study, BEAS-2B cells were treated by TiO2 NPs (0, 25, 50 and 100 µg/mL) for 48 h. The metabolites extracted from BEAS-2B cells were determined by untargeted metabolomics technique, and the differential metabolites and metabolic pathways were discovered by using multivariate analysis. Intracellular ROS was detected by DCFH-DA probe and flow cytometry method. Machine learning was used to explore the relationship between ROS and metabolomics changes. Totally, seventy-six differential metabolites and the steroid biosynthesis pathway of BEAS-2B cells were observed after treatment of TiO2 NPs. Lipid and lipid-like metabolites were the most significant classes among the metabolite products induced by TiO2 NPs. TiO2 NPs resulted in a dose-dependent increase in intracellular ROS levels, and correlated with most of the differential metabolites. In conclusion, TiO2 NPs increased the level of the oxidative stress, which could contribute to the altered signature represented by lipid metabolism in BEAS-2B cells.


Assuntos
Nanopartículas Metálicas , Nanopartículas , Humanos , Lipídeos , Metabolômica , Nanopartículas Metálicas/toxicidade , Nanopartículas/toxicidade , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Titânio/toxicidade
11.
Int J Med Sci ; 19(4): 701-710, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35582421

RESUMO

Wnt signaling is relevant for a wide range of biological processes, including reproductive function. The function of Wnt10a in female fertility, however, remains obscure. In the present study, we explored the structure and function of the female reproductive organs in Wnt10a knockout (KO) mice. The expression of ß-catenin signaling was significantly lower in the ovaries of the Wnt10a KO mice compared with wild-type (WT) mice. In addition, the estrous cycles were disrupted, ovarian follicles were diminished, and endometria were thinner, accompanied by lower serum estrogen levels, and higher testosterone and progesterone levels in Wnt10a KO mice. The expression of the ovarian cytochrome P450 family 19 subfamily A member 1 (Cyp19a1) was significantly lower in Wnt10a KO mice. We detected no significant changes in the levels of the gonadotropins between WT and KO mice. Together, our findings indicate that deficiency of Wnt10a causes female infertility through ß-catenin and Cyp19a1signaling pathways in mice.


Assuntos
Infertilidade Feminina , Proteínas Wnt , beta Catenina , Animais , Aromatase/genética , Aromatase/metabolismo , Feminino , Humanos , Infertilidade Feminina/genética , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/metabolismo , Ovário , Proteínas Wnt/genética , Via de Sinalização Wnt , beta Catenina/genética , beta Catenina/metabolismo
12.
Part Fibre Toxicol ; 19(1): 53, 2022 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-35922847

RESUMO

BACKGROUND: The application of titanium dioxide nanoparticles (TiO2 NPs) as food additives poses a risk of oral exposure that may lead to adverse health effects. Even though the substantial evidence supported liver as the target organ of TiO2 NPs via oral exposure, the mechanism of liver toxicity remains largely unknown. Since the liver is a key organ for lipid metabolism, this study focused on the landscape of lipidomic metabolites in gut-liver axis of Sprague Dawley (SD) rats exposed to TiO2 NPs at 0, 2, 10, 50 mg/kg body weight per day for 90 days. RESULTS: TiO2 NPs (50 mg/kg) caused slight hepatotoxicity and changed lipidomic signatures of main organs or systems in the gut-liver axis including liver, serum and gut. The cluster profile from the above biological samples all pointed to the same key metabolic pathway and metabolites, which was glycerophospholipid metabolism and Phosphatidylcholines (PCs), respectively. In addition, absolute quantitative lipidomics verified the changes of three PCs concentrations, including PC (16:0/20:1), PC (18:0/18:0) and PC (18:2/20:2) in the serum samples after treatment of TiO2 NPs (50 mg/kg). The contents of malondialdehyde (MDA) in serum and liver increased significantly, which were positively correlated with most differential lipophilic metabolites. CONCLUSIONS: The gut was presumed to be the original site of oxidative stress and disorder of lipid metabolism, which resulted in hepatotoxicity through the gut-liver axis. Lipid peroxidation may be the initial step of lipid metabolism disorder induced by TiO2 NPs. Most nanomaterials (NMs) have oxidation induction and antibacterial properties, so the toxic pathway revealed in the present study may be primary and universal.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Nanopartículas , Animais , Lipidômica , Nanopartículas/toxicidade , Estresse Oxidativo , Ratos , Ratos Sprague-Dawley , Titânio/toxicidade
13.
Neuroimage ; 242: 118466, 2021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34389443

RESUMO

Functional connectivity (FC), or the statistical interdependence of blood-oxygen dependent level (BOLD) signals between brain regions using fMRI, has emerged as a widely used tool for probing functional abnormalities in clinical populations due to the promise of the approach across conceptual, technical, and practical levels. With an already vast and steadily accumulating neuroimaging literature on neurodevelopmental, psychiatric, and neurological diseases and disorders in which FC is a primary measure, we aim here to provide a high-level synthesis of major concepts that have arisen from FC findings in a manner that cuts across different clinical conditions and sheds light on overarching principles. We highlight that FC has allowed us to discover the ubiquity of intrinsic functional networks across virtually all brains and clarify typical patterns of neurodevelopment over the lifespan. This understanding of typical FC maturation with age has provided important benchmarks against which to evaluate divergent maturation in early life and degeneration in late life. This in turn has led to the important insight that many clinical conditions are associated with complex, distributed, network-level changes in the brain, as opposed to solely focal abnormalities. We further emphasize the important role that FC studies have played in supporting a dimensional approach to studying transdiagnostic clinical symptoms and in enhancing the multimodal characterization and prediction of the trajectory of symptom progression across conditions. We highlight the unprecedented opportunity offered by FC to probe functional abnormalities in clinical conditions where brain function could not be easily studied otherwise, such as in disorders of consciousness. Lastly, we suggest high priority areas for future research and acknowledge critical barriers associated with the use of FC methods, particularly those related to artifact removal, data denoising and feasibility in clinical contexts.


Assuntos
Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Encéfalo/fisiologia , Estado de Consciência , Humanos , Aprendizagem , Rede Nervosa
14.
Cereb Cortex ; 30(1): 72-84, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31058917

RESUMO

"Superagers" are older adults who, despite their advanced age, maintain youthful memory. Previous morphometry studies revealed multiple default mode network (DMN) and salience network (SN) regions whose cortical thickness is greater in superagers and correlates with memory performance. In this study, we examined the intrinsic functional connectivity within DMN and SN in 41 young (24.5 ± 3.6 years old) and 40 older adults (66.9 ± 5.5 years old). Superaging was defined as youthful performance on a memory recall task, the California Verbal Learning Test (CVLT). Participants underwent a resting-state functional magnetic resonance imaging (fMRI) scan and performed a separate visual-verbal recognition memory task. As predicted, within both DMN and SN, superagers had stronger connectivity compared with typical older adults and similar connectivity compared with young adults. Superagers also performed similarly to young adults and better than typical older adults on the recognition task, demonstrating youthful episodic memory that generalized across memory tasks. Stronger connectivity within each network independently predicted better performance on both the CVLT and recognition task in older adults. Variation in intrinsic connectivity explained unique variance in memory performance, above and beyond youthful neuroanatomy. These results extend our understanding of the neural basis of superaging as a model of successful aging.


Assuntos
Envelhecimento/fisiologia , Envelhecimento/psicologia , Rede de Modo Padrão/fisiologia , Rememoração Mental/fisiologia , Reconhecimento Psicológico/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Memória Episódica , Pessoa de Meia-Idade , Adulto Jovem
15.
Cereb Cortex ; 30(3): 1357-1365, 2020 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-31504277

RESUMO

Degree centrality is a widely used measure in complex networks. Within the brain, degree relates to other topological features, with high-degree nodes (i.e., hubs) exhibiting high betweenness centrality, participation coefficient, and within-module z-score. However, increasing evidence from neuroanatomical and predictive processing literature suggests that topological properties of a brain network may also be impacted by topography, that is, anatomical (spatial) distribution. More specifically, cortical limbic areas (agranular and dysgranular cortices), which occupy an anatomically central position, have been proposed to be topologically central and well suited to initiate predictions in the cerebral cortex. We estimated anatomical centrality and showed that it positively correlated with betweenness centrality, participation coefficient, and communicability, analogously to degree. In contrast to degree, however, anatomical centrality negatively correlated with within-module z-score. Our data suggest that degree centrality and anatomical centrality reflect distinct contributions to cortical organization. Whereas degree would be more related to the amount of information integration performed by an area, anatomical centrality would be more related to an area's position in the predictive hierarchy. Highly anatomically central areas may function as "high-level connectors," integrating already highly integrated information across modules. These results are consistent with a high-level, domain-general limbic workspace, integrated by highly anatomically central cortical areas.


Assuntos
Córtex Cerebral/anatomia & histologia , Conectoma/métodos , Adulto , Feminino , Humanos , Sistema Límbico/anatomia & histologia , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/anatomia & histologia , Adulto Jovem
16.
Opt Express ; 28(8): 12487-12497, 2020 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-32403745

RESUMO

We present the bifunctional design of a broadband absorber and a broadband polarization converter based on a switchable metasurface through the insulator-to-metal phase transition of vanadium dioxide. When vanadium dioxide is metal, the designed switchable metasurface behaves as a broadband absorber. This absorber is composed of a vanadium dioxide square, silica spacer, and vanadium dioxide film. Calculated results show that in the frequency range of 0.52-1.2 THz, the designed system can absorb more than 90% of the energy, and the bandwidth ratio is 79%. It is insensitive to polarization due to the symmetry, and can still work well even at large incident angles. When vanadium dioxide is an insulator, a terahertz polarizer is realized by a simple anisotropic metasurface. Numerical calculation shows that efficient conversion between two orthogonal linear polarizations can be achieved. Reflectance of a cross-polarized wave can reach 90% from 0.42 THz to 1.04 THz, and the corresponding bandwidth ratio is 85%. This cross-polarized converter has the advantages of wide angle, broad bandwidth, and high efficiency. So our design can realize bifunctionality of broadband absorption and polarization conversion between 0.52 THz and 1.04 THz. This architecture could provide one new way to develop switchable photonic devices and functional components in phase change materials.

17.
Opt Express ; 28(2): 2037-2044, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32121902

RESUMO

A multilayer metamaterial with switchable functionalities is presented based on the phase-transition property of vanadium dioxide. When vanadium dioxide is in the metallic state, a broadband absorber is formed. Calculated results show that the combination of two absorption peaks enables absorptance more than 90% in the wide spectral range from 0.393 THz to 0.897 THz. Absorption performance is insensitive to polarization at the small incident angle and work well even at the larger incident angle. When vanadium dioxide is in the insulating state, the designed system behaves as a narrowband absorber at the frequency of 0.677 THz. This narrowband absorber shows the advantages of wide angle and polarization insensitivity due to the localized magnetic resonance. Furthermore, the influences of geometrical parameters on the performance of absorptance are discussed. The proposed switchable absorber can be used in various applications, such as selective heat emitter and solar photovoltaic field.

18.
Waste Manag Res ; 38(12): 1389-1404, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33008283

RESUMO

This study summarized global examples of landfill slope instability over the past 40 years, then selected 62 cases from 22 different counties to analyse the primary factors causing landfill instability. Three slope instability modes in landfill were categorized according to the position of the slip surface: (1) slip surfaces generated inside the waste pile; (2) slip surfaces that pass through the foundation soil; and (3) slip surfaces that occur along the interface between the bottom liner and the municipal solid waste (MSW) pile. These three types of slope instability modes account for 69.4%, 19.32% and 11.28% of all slope instability, respectively. Moreover, five primary causes of landfill instability were identified. A high landfill leachate level was the dominant cause, accounting for 40.32% of cases. This was followed by inadequate compaction of MSW, which accounted for 22.58% of cases, and insufficiently bearing capacity of the foundation, which accounted for 19.35% of cases. Moreover, low shear strength of the liner-MSW interface and rapid release or deflagration of landfill gas were critical factors affecting landfill stability. Factors of safety were calculated using GeoStudio software for selected landfills in China (Maoershan and Xiaping) and Sri Lanka (Meethotamulla). Results from this study are expected to contribute to the prevention and control of landfill failure.


Assuntos
Eliminação de Resíduos , Poluentes Químicos da Água , Reatores Biológicos , China , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos , Poluentes Químicos da Água/análise
19.
Opt Express ; 27(18): 25196-25204, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31510396

RESUMO

A switchable metamaterial with bifunctionality of absorption and electromagnetically induced transparency is proposed based on the phase-transition characteristic of phase change material-vanadium dioxide. When vanadium dioxide is in the metallic state, an isotropic narrow absorber is obtained in the terahertz region, which consists of a top metallic cross, a middle dielectric layer, and a bottom vanadium dioxide film. By adjusting structure parameters, perfect absorption is realized at the frequency of 0.498 THz. This designed narrow absorber is insensitive to polarization and incident angle. Absorptance can still reach 75% for transverse electric polarization and transverse magnetic polarization at the incident angle of 65∘. When vanadium dioxide is in the insulating state, the top metallic cross will interact with the bottom split ring resonator, and the interaction between them will lead to the appearance of electromagnetically induced transparency. The behavior of electromagnetically induced transparency works well for transverse electric polarization and transverse magnetic polarization at the small incident angle. The designed hybrid metamaterial opens possible avenues for achieving switchable functionalities in a single device.

20.
Neuroimage ; 132: 190-197, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-26899785

RESUMO

Successful navigation of the environment requires attending and responding efficiently to objects and conspecifics with the potential to benefit or harm (i.e., that have value). In humans, this function is subserved by a distributed large-scale neural network called the "salience network". We have recently demonstrated that there are two anatomically and functionally dissociable salience networks anchored in the dorsal and ventral portions of the human anterior insula (Touroutoglou et al., 2012). In this paper, we test the hypothesis that these two subnetworks exist in rhesus macaques (Macaca mulatta). We provide evidence that a homologous ventral salience network exists in macaques, but that the connectivity of the dorsal anterior insula in macaques is not sufficiently developed as a dorsal salience network. The evolutionary implications of these finding are considered.


Assuntos
Atenção/fisiologia , Córtex Cerebral/fisiologia , Macaca mulatta/fisiologia , Animais , Encéfalo/fisiologia , Mapeamento Encefálico , Feminino , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/fisiologia , Especificidade da Espécie
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