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1.
Nature ; 601(7894): 562-567, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35082417

RESUMO

In conventional superconductors, the phase transition into a zero-resistance and perfectly diamagnetic state is accompanied by a jump in the specific heat and the opening of a spectral gap1. In the high-transition-temperature (high-Tc) cuprates, although the transport, magnetic and thermodynamic signatures of Tc have been known since the 1980s2, the spectroscopic singularity associated with the transition remains unknown. Here we resolve this long-standing puzzle with a high-precision angle-resolved photoemission spectroscopy (ARPES) study on overdoped (Bi,Pb)2Sr2CaCu2O8+δ (Bi2212). We first probe the momentum-resolved electronic specific heat via spectroscopy and reproduce the specific heat peak at Tc, completing the missing link for a holistic description of superconductivity. Then, by studying the full momentum, energy and temperature evolution of the spectra, we reveal that this thermodynamic anomaly arises from the singular growth of in-gap spectral intensity across Tc. Furthermore, we observe that the temperature evolution of in-gap intensity is highly anisotropic in the momentum space, and the gap itself obeys both the d-wave functional form and particle-hole symmetry. These findings support the scenario that the superconducting transition is driven by phase fluctuations. They also serve as an anchor point for understanding the Fermi arc and pseudogap phenomena in underdoped cuprates.

2.
Nature ; 604(7907): 771-778, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35418677

RESUMO

Adhesion G protein-coupled receptors (aGPCRs) constitute an evolutionarily ancient family of receptors that often undergo autoproteolysis to produce α and ß subunits1-3. A tethered agonism mediated by the 'Stachel sequence' of the ß subunit has been proposed to have central roles in aGPCR activation4-6. Here we present three cryo-electron microscopy structures of aGPCRs coupled to the Gs heterotrimer. Two of these aGPCRs are activated by tethered Stachel sequences-the ADGRG2-ß-Gs complex and the ADGRG4-ß-Gs complex (in which ß indicates the ß subunit of the aGPCR)-and the other is the full-length ADGRG2 in complex with the exogenous ADGRG2 Stachel-sequence-derived peptide agonist IP15 (ADGRG2(FL)-IP15-Gs). The Stachel sequences of both ADGRG2-ß and ADGRG4-ß assume a U shape and insert deeply into the seven-transmembrane bundles. Constituting the FXφφφXφ motif (in which φ represents a hydrophobic residue), five residues of ADGRG2-ß or ADGRG4-ß extend like fingers to mediate binding to the seven-transmembrane domain and activation of the receptor. The structure of the ADGRG2(FL)-IP15-Gs complex reveals the structural basis for the improved binding affinity of IP15 compared with VPM-p15 and indicates that rational design of peptidic agonists could be achieved by exploiting aGPCR-ß structures. By converting the 'finger residues' to acidic residues, we develop a method to generate peptidic antagonists towards several aGPCRs. Collectively, our study provides structural and biochemical insights into the tethered activation mechanism of aGPCRs.


Assuntos
Peptídeos , Receptores Acoplados a Proteínas G , Microscopia Crioeletrônica , Humanos , Peptídeos/metabolismo , Domínios Proteicos , Receptores Acoplados a Proteínas G/metabolismo
3.
N Engl J Med ; 388(20): 1843-1852, 2023 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-37195940

RESUMO

BACKGROUND: Previous studies have suggested that a single dose of rifampin has protective effects against leprosy in close contacts of patients with the disease. Rifapentine was shown to have greater bactericidal activity against Mycobacterium leprae than rifampin in murine models of leprosy, but data regarding its effectiveness in preventing leprosy are lacking. METHODS: We conducted a cluster-randomized, controlled trial to investigate whether single-dose rifapentine is effective in preventing leprosy in household contacts of patients with leprosy. The clusters (counties or districts in Southwest China) were assigned to one of three trial groups: single-dose rifapentine, single-dose rifampin, or control (no intervention). The primary outcome was the 4-year cumulative incidence of leprosy among household contacts. RESULTS: A total of 207 clusters comprising 7450 household contacts underwent randomization; 68 clusters (2331 household contacts) were assigned to the rifapentine group, 71 (2760) to the rifampin group, and 68 (2359) to the control group. A total of 24 new cases of leprosy occurred over the 4-year follow-up, for a cumulative incidence of 0.09% (95% confidence interval [CI], 0.02 to 0.34) with rifapentine (2 cases), 0.33% (95% CI, 0.17 to 0.63) with rifampin (9 cases), and 0.55% (95% CI, 0.32 to 0.95) with no intervention (13 cases). In an intention-to-treat analysis, the cumulative incidence in the rifapentine group was 84% lower than that in the control group (cumulative incidence ratio, 0.16; multiplicity-adjusted 95% CI, 0.03 to 0.87; P = 0.02); the cumulative incidence did not differ significantly between the rifampin group and the control group (cumulative incidence ratio, 0.59; multiplicity-adjusted 95% CI, 0.22 to 1.57; P = 0.23). In a per-protocol analysis, the cumulative incidence was 0.05% with rifapentine, 0.19% with rifampin, and 0.63% with no intervention. No severe adverse events were observed. CONCLUSIONS: The incidence of leprosy among household contacts over 4 years was lower with single-dose rifapentine than with no intervention. (Funded by the Ministry of Health of China and the Chinese Academy of Medical Sciences; Chinese Clinical Trial Registry number, ChiCTR-IPR-15007075.).


Assuntos
Hansenostáticos , Hanseníase , Mycobacterium leprae , Rifampina , Humanos , Incidência , Hanseníase/epidemiologia , Hanseníase/prevenção & controle , Hanseníase/transmissão , Rifampina/administração & dosagem , Rifampina/análogos & derivados , Hansenostáticos/administração & dosagem , Hansenostáticos/uso terapêutico , Características da Família
4.
J Immunol ; 2024 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-39400236

RESUMO

Hepatitis B virus (HBV) is the most common chronic viral infection globally, affecting ∼360 million people and causing about 1 million deaths annually due to end-stage liver disease or hepatocellular carcinoma. Current antiviral treatments rarely achieve a functional cure for chronic hepatitis B, highlighting the need for improved monitoring and intervention strategies. This study explores the role of the sphingosine kinase 1 (SphK1)-sphingosine-1-phosphate (S1P) axis in HBV-related liver injury. We investigated the association between serum S1P concentration and HBV DNA levels in chronic hepatitis B patients, finding a significant positive correlation. Additionally, SphK1 was elevated in liver tissues of HBV-positive hepatocellular carcinoma patients, particularly in HBsAg-positive regions. HBV infection models in HepG2-sodium taurocholate cotransporting polypeptide cells confirmed that HBV enhances SphK1 expression and S1P production. Inhibition of HBV replication through antiviral agents and the CRISPR-Cas9 system reduced SphK1 and S1P levels. Further, we identified the transcription factor USF1 as a key regulator of SphK1 expression during HBV infection. USF1 binds to the SphK1 promoter, increasing its transcriptional activity, and is upregulated in response to HBV infection. In vivo studies in mice demonstrated that HBV exposure promotes the expression of USF1 and SphK1-S1P. These findings suggest that the SphK1-S1P axis, regulated by HBV-induced USF1, could serve as a potential biomarker and therapeutic target for HBV-related liver injury.

5.
Plant J ; 119(1): 283-299, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38606500

RESUMO

Drought stress is one of the dominating challenges to the growth and productivity in crop plants. Elucidating the molecular mechanisms of plants responses to drought stress is fundamental to improve fruit quality. However, such molecular mechanisms are poorly understood in apple (Malus domestica Borkh.). In this study, we explored that the BTB-BACK-TAZ protein, MdBT2, negatively modulates the drought tolerance of apple plantlets. Moreover, we identified a novel Homeodomain-leucine zipper (HD-Zip) transcription factor, MdHDZ27, using a yeast two-hybrid (Y2H) screen with MdBT2 as the bait. Overexpression of MdHDZ27 in apple plantlets, calli, and tomato plantlets enhanced their drought tolerance by promoting the expression of drought tolerance-related genes [responsive to dehydration 29A (MdRD29A) and MdRD29B]. Biochemical analyses demonstrated that MdHDZ27 directly binds to and activates the promoters of MdRD29A and MdRD29B. Furthermore, in vitro and in vivo assays indicate that MdBT2 interacts with and ubiquitinates MdHDZ27, via the ubiquitin/26S proteasome pathway. This ubiquitination results in the degradation of MdHDZ27 and weakens the transcriptional activation of MdHDZ27 on MdRD29A and MdRD29B. Finally, a series of transgenic analyses in apple plantlets further clarified the role of the relationship between MdBT2 and MdHDZ27, as well as the effect of their interaction on drought resistance in apple plantlets. Collectively, our findings reveal a novel mechanism by which the MdBT2-MdHDZ27 regulatory module controls drought tolerance, which is of great significance for enhancing the drought resistance of apple and other plants.


Assuntos
Resistência à Seca , Malus , Proteínas de Plantas , Fatores de Transcrição , Ubiquitinação , Resistência à Seca/genética , Regulação da Expressão Gênica de Plantas , Malus/genética , Malus/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estresse Fisiológico , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
6.
Nat Mater ; 23(6): 810-817, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38684883

RESUMO

For halide perovskites that are susceptible to photolysis and ion migration, iodide-related defects, such as iodine (I2) and iodine vacancies, are inevitable. Even a small number of these defects can trigger self-accelerating chemical reactions, posing serious challenges to the durability of perovskite solar cells. Fortunately, before I2 can damage the perovskites under illumination, they generally diffuse over a long distance. Therefore, detrimental I2 can be captured by interfacial materials with strong iodide/polyiodide (Ix-) affinities, such as fullerenes and perfluorodecyl iodide. However, fullerenes in direct contact with perovskites fail to confine Ix- ions within the perovskite layer but cause detrimental iodine vacancies. Perfluorodecyl iodide, with its directional Ix- affinity through halogen bonding, can both capture and confine Ix-. Therefore, inverted perovskite solar cells with over 10 times improved ultraviolet irradiation and thermal-light stabilities (under 85 °C and 1 sun illumination), and 1,000 times improved reverse-bias stability (under ISOS-V ageing tests) have been developed.

7.
Plant Physiol ; 195(2): 1382-1400, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38345866

RESUMO

Brassinosteroids (BRs) are phytohormones that regulate stomatal development. In this study, we report that BR represses stomatal development in etiolated Arabidopsis (Arabidopsis thaliana) cotyledons via transcription factors BRASSINAZOLE RESISTANT 1 (BZR1) and bri1-EMS SUPPRESSOR1 (BES1), which directly target MITOGEN-ACTIVATED PROTEIN KINASE KINASE 9 (MKK9) and FAMA, 2 important genes for stomatal development. BZR1/BES1 bind MKK9 and FAMA promoters in vitro and in vivo, and mutation of the BZR1/BES1 binding motif in MKK9/FAMA promoters abolishes their transcription regulation by BZR1/BES1 in plants. Expression of a constitutively active MKK9 (MKK9DD) suppressed overproduction of stomata induced by BR deficiency, while expression of a constitutively inactive MKK9 (MKK9KR) induced high-density stomata in bzr1-1D. In addition, bzr-h, a sextuple mutant of the BZR1 family of proteins, produced overabundant stomata, and the dominant bzr1-1D and bes1-D mutants effectively suppressed the stomata-overproducing phenotype of brassinosteroid insensitive 1-116 (bri1-116) and brassinosteroid insensitive 2-1 (bin2-1). In conclusion, our results revealed important roles of BZR1/BES1 in stomatal development, and their transcriptional regulation of MKK9 and FAMA expression may contribute to BR-regulated stomatal development in etiolated Arabidopsis cotyledons.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Brassinosteroides , Cotilédone , Proteínas de Ligação a DNA , Regulação da Expressão Gênica de Plantas , Proteínas Nucleares , Estômatos de Plantas , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Brassinosteroides/metabolismo , Estômatos de Plantas/crescimento & desenvolvimento , Estômatos de Plantas/genética , Estômatos de Plantas/efeitos dos fármacos , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Cotilédone/metabolismo , Cotilédone/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Mutação/genética , Regiões Promotoras Genéticas/genética , Estiolamento , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Ligação Proteica/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/genética
8.
Chromosome Res ; 32(2): 5, 2024 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-38502277

RESUMO

Artemisia is a large genus encompassing about 400 diverse species, many of which have considerable medicinal and ecological value. However, complex morphological information and variation in ploidy level and nuclear DNA content have presented challenges for evolution studies of this genus. Consequently, taxonomic inconsistencies within the genus persist, hindering the utilization of such large plant resources. Researchers have utilized satellite DNAs to aid in chromosome identification, species classification, and evolutionary studies due to their significant sequence and copy number variation between species and close relatives. In the present study, the RepeatExplorer2 pipeline was utilized to identify 10 satellite DNAs from three species (Artemisia annua, Artemisia vulgaris, Artemisia viridisquama), and fluorescence in situ hybridization confirmed their distribution on chromosomes in 24 species, including 19 Artemisia species with 5 outgroup species from Ajania and Chrysanthemum. Signals of satellite DNAs exhibited substantial differences between species. We obtained one genus-specific satellite from the sequences. Additionally, molecular cytogenetic maps were constructed for Artemisia vulgaris, Artemisia leucophylla, and Artemisia viridisquama. One species (Artemisia verbenacea) showed a FISH distribution pattern suggestive of an allotriploid origin. Heteromorphic FISH signals between homologous chromosomes in Artemisia plants were observed at a high level. Additionally, the relative relationships between species were discussed by comparing ideograms. The results of the present study provide new insights into the accurate identification and taxonomy of the Artemisia genus using molecular cytological methods.


Assuntos
Artemisia , Artemisia/genética , Hibridização in Situ Fluorescente , Filogenia , DNA Satélite/genética , Variações do Número de Cópias de DNA
9.
Brain ; 147(10): 3395-3408, 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-38454550

RESUMO

Hearing difficulty (HD) is a major health burden in older adults. While ageing-related changes in the peripheral auditory system play an important role, genetic variation associated with brain structure and function could also be involved in HD predisposition. We analysed a large-scale HD genome-wide association study (GWAS; ntotal = 501 825, 56% females) and GWAS data related to 3935 brain imaging-derived phenotypes (IDPs) assessed in up to 33 224 individuals (52% females) using multiple MRI modalities. To investigate HD pleiotropy with brain structure and function, we conducted genetic correlation, latent causal variable, Mendelian randomization and multivariable generalized linear regression analyses. Additionally, we performed local genetic correlation and multi-trait co-localization analyses to identify genomic regions and loci implicated in the pleiotropic mechanisms shared between HD and brain IDPs. We observed a widespread genetic correlation of HD with 120 IDPs in females, 89 in males and 171 in the sex-combined analysis. The latent causal variable analysis showed that some of these genetic correlations could be due to cause-effect relationships. For seven of them, the causal effects were also confirmed by the Mendelian randomization approach: vessel volume→HD in the sex-combined analysis; hippocampus volume→HD, cerebellum grey matter volume→HD, primary visual cortex volume→HD and HD→fluctuation amplitudes of node 46 in resting-state functional MRI dimensionality 100 in females; global mean thickness→HD and HD→mean orientation dispersion index in superior corona radiata in males. The local genetic correlation analysis identified 13 pleiotropic regions between HD and these seven IDPs. We also observed a co-localization signal for the rs13026575 variant between HD, primary visual cortex volume and SPTBN1 transcriptomic regulation in females. Brain structure and function may have a role in the sex differences in HD predisposition via possible cause-effect relationships and shared regulatory mechanisms.


Assuntos
Encéfalo , Pleiotropia Genética , Estudo de Associação Genômica Ampla , Perda Auditiva , Imageamento por Ressonância Magnética , Fenótipo , Caracteres Sexuais , Humanos , Feminino , Masculino , Encéfalo/diagnóstico por imagem , Perda Auditiva/genética , Perda Auditiva/fisiopatologia , Idoso , Pessoa de Meia-Idade , Análise da Randomização Mendeliana
10.
Nature ; 568(7751): 240-243, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30944466

RESUMO

The plant hormone auxin has crucial roles in almost all aspects of plant growth and development. Concentrations of auxin vary across different tissues, mediating distinct developmental outcomes and contributing to the functional diversity of auxin. However, the mechanisms that underlie these activities are poorly understood. Here we identify an auxin signalling mechanism, which acts in parallel to the canonical auxin pathway based on the transport inhibitor response1 (TIR1) and other auxin receptor F-box (AFB) family proteins (TIR1/AFB receptors)1,2, that translates levels of cellular auxin to mediate differential growth during apical-hook development. This signalling mechanism operates at the concave side of the apical hook, and involves auxin-mediated C-terminal cleavage of transmembrane kinase 1 (TMK1). The cytosolic and nucleus-translocated C terminus of TMK1 specifically interacts with and phosphorylates two non-canonical transcriptional repressors of the auxin or indole-3-acetic acid (Aux/IAA) family (IAA32 and IAA34), thereby regulating ARF transcription factors. In contrast to the degradation of Aux/IAA transcriptional repressors in the canonical pathway, the newly identified mechanism stabilizes the non-canonical IAA32 and IAA34 transcriptional repressors to regulate gene expression and ultimately inhibit growth. The auxin-TMK1 signalling pathway originates at the cell surface, is triggered by high levels of auxin and shares a partially overlapping set of transcription factors with the TIR1/AFB signalling pathway. This allows distinct interpretations of different concentrations of cellular auxin, and thus enables this versatile signalling molecule to mediate complex developmental outcomes.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Ácidos Indolacéticos/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Sequência de Aminoácidos , Arabidopsis/citologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas F-Box/metabolismo , Ácidos Indolacéticos/antagonistas & inibidores , Mutação , Reguladores de Crescimento de Plantas/antagonistas & inibidores , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética , Receptores de Superfície Celular/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo
11.
Cereb Cortex ; 34(3)2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-38466115

RESUMO

Mild cognitive impairment plays a crucial role in predicting the early progression of Alzheimer's disease, and it can be used as an important indicator of the disease progression. Currently, numerous studies have focused on utilizing the functional brain network as a novel biomarker for mild cognitive impairment diagnosis. In this context, we employed a graph convolutional neural network to automatically extract functional brain network features, eliminating the need for manual feature extraction, to improve the mild cognitive impairment diagnosis performance. However, previous graph convolutional neural network approaches have primarily concentrated on single modes of brain connectivity, leading to a failure to leverage the potential complementary information offered by diverse connectivity patterns and limiting their efficacy. To address this limitation, we introduce a novel method called the graph convolutional neural network with multimodel connectivity, which integrates multimode connectivity for the identification of mild cognitive impairment using fMRI data and evaluates the graph convolutional neural network with multimodel connectivity approach through a mild cognitive impairment diagnostic task on the Alzheimer's Disease Neuroimaging Initiative dataset. Overall, our experimental results show the superiority of the proposed graph convolutional neural network with multimodel connectivity approach, achieving an accuracy rate of 92.2% and an area under the Receiver Operating Characteristic (ROC) curve of 0.988.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , Imageamento por Ressonância Magnética , Doença de Alzheimer/diagnóstico por imagem , Neuroimagem , Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem
12.
Nano Lett ; 24(26): 7843-7851, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38912682

RESUMO

Two-dimensional-material-based memristors are emerging as promising enablers of new computing systems beyond von Neumann computers. However, the most studied anion-vacancy-enabled transition metal dichalcogenide memristors show many undesirable performances, e.g., high leakage currents, limited memory windows, high programming currents, and limited endurance. Here, we demonstrate that the emergent van der Waals metal phosphorus trisulfides with unconventional nondefective vacancy provide a promising paradigm for high-performance memristors. The different vacancy types (i.e., defective and nondefective vacancies) induced memristive discrepancies are uncovered. The nondefective vacancies can provide an ultralow diffusion barrier and good memristive structure stability giving rise to many desirable memristive performances, including high off-state resistance of 1012 Ω, pA-level programming currents, large memory window up to 109, more than 7-bit conductance states, and good endurance. Furthermore, a high-yield (94%) memristor crossbar array is fabricated and implements multiple image processing successfully, manifesting the potential for in-memory computing hardware.

13.
Nano Lett ; 24(6): 2118-2124, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38305203

RESUMO

Ferroelectric two-dimensional (2D) materials with a high transition temperature are highly desirable for new physics and next-generation memory electronics. However, the long-range polar order of ferroelectrics will barely persist when the thickness reaches the nanoscale. In this work, we synthesized 2D CuCrS2 nanosheets with thicknesses down to one unit cell via van der Waals epitaxy in a chemical vapor deposition system. A combination of transmission electron microscopy, second-harmonic generation, and Raman spectroscopy measurements confirms the R3m space group and noncentrosymmetric structure. Switchable ferroelectric domains and obvious ferroelectric hysteresis loops were created and visualized by piezoresponse force microscopy. Theoretical calculation helps us understand the mechanism of ferroelectric switching in CuCrS2 nanosheets. Finally, we fabricated a ferroelectric memory device that achieves an on/off ratio of ∼102 and remains stable after 2000 s, indicating its applicability in novel nanoelectronics. Overall, 2D CuCrS2 nanosheets exhibit excellent ferroelectric properties at the nanoscale, showing great promise for next-generation devices.

14.
Nano Lett ; 24(19): 5862-5869, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38709809

RESUMO

Dynamic vision perception and processing (DVPP) is in high demand by booming edge artificial intelligence. However, existing imaging systems suffer from low efficiency or low compatibility with advanced machine vision techniques. Here, we propose a reconfigurable bipolar image sensor (RBIS) for in-sensor DVPP based on a two-dimensional WSe2/GeSe heterostructure device. Owing to the gate-tunable and reversible built-in electric field, its photoresponse shows bipolarity as being positive or negative. High-efficiency DVPP incorporating front-end RBIS and back-end CNN is then demonstrated. It shows a high recognition accuracy of over 94.9% on the derived DVS128 data set and requires much fewer neural network parameters than that without RBIS. Moreover, we demonstrate an optimized device with a vertically stacked structure and a stable nonvolatile bipolarity, which enables more efficient DVPP hardware. Our work demonstrates the potential of fabricating DVPP devices with a simple structure, high efficiency, and outputs compatible with advanced algorithms.

15.
Nano Lett ; 24(26): 8189-8197, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38904278

RESUMO

IV-V two-dimensional materials have emerged as key contenders for polarization-sensitive and angle-resolved devices, given their inherent anisotropic physical properties. While these materials exhibit intriguing high-pressure quasi-particle behavior and phase transition, the evolution of quasi-particles and their interactions under external pressure remain elusive. Here, employing a diamond anvil cell and spectroscopic measurements coupled with first-principles calculations, we unveil rarely observed pressure-induced phonon-phonon coupling in layered SiP flakes. This coupling manifests as an anomalous phonon hardening behavior for the A1 mode within a broad wavenumber phonon softening region. Furthermore, we demonstrate the effective tuning of exciton emissions in SiP flakes under pressure, revealing a remarkable 63% enhancement in the degree of polarization (DOP) within the pressure range of 0-3.5 GPa. These findings contribute to our understanding of high-pressure phonon evolution in SiP materials and offer a strategic approach to manipulate the anisotropic performance of in-plane anisotropic 2D materials.

16.
Nano Lett ; 24(30): 9186-9194, 2024 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-39012034

RESUMO

The interaction between light and moiré superlattices presents a platform for exploring unique light-matter phenomena. Tailoring these optical properties holds immense potential for advancing the utilization of moiré superlattices in photonics, optoelectronics, and valleytronics. However, the control of the optical polarization state in moiré superlattices, particularly in the presence of moiré effects, remains elusive. Here, we unveil the emergence of optical anisotropy in moiré superlattices by constructing twisted WSe2/WSe2/SiP heterostructures. We report a linear polarization degree of ∼70% for moiré excitons, attributed to the spatially nonuniform charge distribution, corroborated by first-principles calculations. Furthermore, we demonstrate the modulation of this linear polarization state via the application of a magnetic field, resulting in polarization angle rotation and a magnetic-field-dependent linear polarization degree, influenced by valley coherence and moiré potential effects. Our findings demonstrate an efficient strategy for tuning the optical polarization state of moiré superlattices using heterointerface engineering.

17.
Nano Lett ; 2024 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-39373390

RESUMO

Domain orientation modulation and controlled doping of two-dimensional (2D) transition-metal dichalcogenides (TMDCs) are two pivotal tasks for synthesizing wafer-scale single crystals and boosting device performances. However, realizing two such targets and uncovering internal physical mechanisms remain daunting challenges. We develop an accurate Fe doping strategy, which enables domain orientation control and electron mobility improvement of monolayer MoS2. By tuning of the Fe dopant dosages, parallel steps with different heights are formed, which induce edge-nucleation of unidirectionally aligned monolayer MoS2. In parallel, Fe doping induces the down shift of the conduction band minimum of monolayer MoS2 and matches well with the work function of an electrode, which reduces Schottky barrier height and delivers ultralow contact resistance (561 Ω µm) and excellent electron mobility (37.5 cm2 V-1 s-1). The modulation mechanism is clarified by combining theory calculations and electronic structure characterizations. This work hereby provides a new paradigm for synthesizing wafer-scale 2D TMDC single crystals and constructing high-performance devices.

18.
Nano Lett ; 24(7): 2408-2414, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38329291

RESUMO

Two-dimensional (2D) heterostructures with ferromagnetism and ferroelectricity provide a promising avenue to miniaturize the device size, increase computational power, and reduce energy consumption. However, the direct synthesis of such eye-catching heterostructures has yet to be realized up to now. Here, we design a two-step chemical vapor deposition strategy to growth of Cr2S3/WS2 vertical heterostructures with atomically sharp and clean interfaces on sapphire. The interlayer charge transfer and periodic moiré superlattice result in the emergence of room-temperature ferroelectricity in atomically thin Cr2S3/WS2 vertical heterostructures. In parallel, long-range ferromagnetic order is discovered in 2D Cr2S3 via the magneto-optical Kerr effect technique with the Curie temperature approaching 170 K. The charge distribution variation induced by the moiré superlattice changes the ferromagnetic coupling strength and enhances the Curie temperature. The coexistence of ferroelectricity and ferromagnetism in 2D Cr2S3/WS2 vertical heterostructures provides a cornerstone for the further design of logic-in-memory devices to build new computing architectures.

19.
Am J Respir Cell Mol Biol ; 71(3): 356-371, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38864771

RESUMO

Pulmonary hypertension (PH) is an incurable disease characterized by pulmonary vascular remodeling. Endothelial injury and inflammation are the key triggers of disease initiation. Recent findings suggest that STING (stimulator of IFN genes) activation plays a critical role in endothelial dysfunction and IFN signaling. Here, we investigated the involvement of STING in the pathogenesis of PH. Patients with PH and rodent PH model samples, a Sugen 5416/hypoxia PH model, and pulmonary artery endothelial cells (PAECs) were used to evaluate the hypothesis. We found that the cyclic guanosine monophosphate-AMP synthase-STING signaling pathway was activated in lung tissues from rodent PH models and patients with PH and in TNF-α-induced PAECs in vitro. Specifically, STING expression was significantly elevated in the endothelial cells in PH disease settings. In the Sugen 5416/hypoxia mouse model, genetic knockout or pharmacological inhibition of STING prevented the progression of PH. Functionally, knockdown of STING reduced the proliferation and migration of PAECs. Mechanistically, STING transcriptionally regulates its binding partner F2RL3 (F2R-like thrombin or trypsin receptor 3) through the STING-NF-κB axis, which activated IFN signaling and repressed BMPR2 (bone morphogenetic protein receptor 2) signaling both in vitro and in vivo. Further analysis revealed that F2RL3 expression was increased in PH settings and identified negative feedback regulation of F2RL3/BMPR2 signaling. Accordingly, a positive correlation of expression amounts between STING and F2RL3/IFN-stimulated genes was observed in vivo. Our findings suggest that STING activation in PAECs plays a critical role in the pathobiology of PH. Targeting STING may be a promising therapeutic strategy for preventing the development of PH.


Assuntos
Receptores de Proteínas Morfogenéticas Ósseas Tipo II , Hipertensão Pulmonar , Proteínas de Membrana , Transdução de Sinais , Animais , Humanos , Masculino , Camundongos , Ratos , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/genética , Proliferação de Células , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/patologia , Hipóxia/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Artéria Pulmonar/metabolismo , Artéria Pulmonar/patologia , Receptores de Trombina/genética , Receptores de Trombina/metabolismo
20.
Am J Physiol Cell Physiol ; 327(1): C65-C73, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38766766

RESUMO

The blood-brain barrier (BBB) plays a critical role in the development and outcome of subarachnoid hemorrhage (SAH). This study focuses on the potential mechanism by which G-protein-coupled estrogen receptor 30 (GPR30) affects the BBB after SAH. A rat SAH model was established using an intravascular perforation approach. G1 (GPR30 agonist) was administered to investigate the mechanism of BBB damage after SAH. Brain water content, Western blotting, Evans blue leakage, and immunofluorescence staining were performed. Brain microvascular endothelial cells were induced by hemin to establish SAH model in vitro. By adding LY294002 [a phosphatidylinositol 3-kinase (PI3K) blocker] and zinc protoporphyrin IX (ZnPP IX) [a heme oxygenase 1 (HO-1) antagonist], the mechanism of improving BBB integrity through the activation of GPR30 was studied. In vivo, GPR30 activation improved BBB disruption, as evidenced by decreased cerebral edema, downregulated albumin expression, and reduced extravasation of Evans blue and IgG after G1 administration in SAH rats. Moreover, SAH downregulated the levels of tight junction (TJ) proteins, whereas treatment with G1 reversed the effect of SAH. The protective effect of G1 on BBB integrity in vitro was consistent with that in vivo, as evidenced by G1 reducing the impact of hemin on transendothelial electrical resistance (TEER) value, dextran diffusivity, and TJ protein levels in brain microvascular endothelial cells. In addition, G1 activated the PI3K/ protein kinase B (Akt) and nuclear factor erythroid 2-related factor 2 (Nrf2)/HO-1 pathways both in vivo and in vitro. Furthermore, the administration of LY294002 and ZnPP IX partially reversed the protective effect of G1 on BBB integrity in hemin-stimulated cells. We demonstrated that the activation of GPR30, at least partly through the PI3K/Akt and Nrf2/HO-1 pathways, alleviated BBB damage both in vivo and in vitro. This study introduced a novel therapeutic approach for protecting the BBB after SAH.NEW & NOTEWORTHY The PI3K/Akt and Nrf2/HO-1 pathways might be potential mechanisms by which GPR30 protected the integrity of the BBB in SAH models. Therefore, treatment of SAH with GPR30 activator might be a promising therapeutic strategy.


Assuntos
Barreira Hematoencefálica , Receptores Acoplados a Proteínas G , Transdução de Sinais , Hemorragia Subaracnóidea , Animais , Masculino , Ratos , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Células Endoteliais/efeitos dos fármacos , Heme Oxigenase (Desciclizante)/metabolismo , Heme Oxigenase-1/metabolismo , Hemina/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/agonistas , Hemorragia Subaracnóidea/metabolismo , Hemorragia Subaracnóidea/patologia , Hemorragia Subaracnóidea/tratamento farmacológico , Hemorragia Subaracnóidea/complicações
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