Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 89
Filtrar
1.
Sci Rep ; 14(1): 23075, 2024 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-39367023

RESUMO

Xiong'an New Area was established as a state-level new area in 2017 and serves as a typical representative area for studying the ecological evolution of rural areas under rapid urbanization in China. Remote sensing-based ecological index (RSEI) is a regional eco-environmental quality (EEQ) assessment index. Many studies have employed RSEI to achieve rapid, objective, and effective quantitative assessment of the spatio-temporal changes of regional EEQ. However, research that combines RSEI with machine learning algorithms to conduct multi-scenario simulation of EEQ is still relatively scarce. Therefore, this study assessed and simulated EEQ changes in Xiong'an and revealed that: (1) The large-scale construction has led to an overall decline in EEQ, with the RSEI decreasing from 0.648 in 2014 to 0.599 in 2021. (2) Through the multi-scenario simulation, the non-unidirectional evolution of RSEI during the process of urban-rural construction has been revealed, specifically characterized by a significant decline followed by a slight recovery. (3) The marginal effects of urban-rural construction features for simulated RSEI demonstrate an inverted "U-shaped" curve in the relationship between urbanization and EEQ. This indicates that urbanization and EEQ may not be absolute zero-sum. These findings can provide scientific insights for maintaining and improving the regional EEQ in urban-rural construction.

2.
Nano Lett ; 24(32): 9923-9930, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39078726

RESUMO

The natural van der Waals superlattice MnBi2Te4-(Bi2Te3)m provides an optimal platform to combine topology and magnetism in one system with minimal structural disorder. Here, we show that this system can harbor both ferromagnetic (FM) and antiferromagnetic (AFM) orders and that these magnetic orders can be controlled in two different ways by either varying the Mn-Mn distance while keeping the Bi2Te3/MnBi2Te4 ratio constant or vice versa. We achieve this by creating atomically engineered sandwich structures composed of Bi2Te3 and MnBi2Te4 layers. We show that the AFM order is exclusively determined by the Mn-Mn distance, whereas the FM order depends only on the overall Bi2Te3/MnBi2Te4 ratio regardless of the distance between the MnBi2Te4 layers. Our results shed light on the origins of the AFM and FM orders and provide insights into how to manipulate magnetic orders not only for the MnBi2Te4-Bi2Te3 system but also for other magneto-topological materials.

3.
ACS Appl Mater Interfaces ; 16(26): 34386-34392, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38869156

RESUMO

Highly crystalline and easily feasible topological insulator-superconductor (TI-SC) heterostructures are crucial for the development of practical topological qubit devices. The optimal superconducting layer for TI-SC heterostructures should be highly resilient against external contamination and structurally compatible with TIs. In this study, we provide a solution to this challenge by showcasing the growth of a highly crystalline TI-SC heterostructure using refractory TiN (111) as the superconducting layer. This approach can eliminate the need for in situ cleavage or growth. More importantly, the TiN surface shows high resilience against contaminations during air exposure, as demonstrated by the successful recyclable growth of Bi2Se3. Our findings indicate that TI-SC heterostructures based on nitride films are compatible with device fabrication techniques, paving the way to the realization of practical topological qubit devices in the future.

4.
Nat Microbiol ; 9(8): 2128-2143, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38858594

RESUMO

Human parainfluenza virus type 3 (hPIV3) is a respiratory pathogen that can cause severe disease in older people and infants. Currently, vaccines against hPIV3 are in clinical trials but none have been approved yet. The haemagglutinin-neuraminidase (HN) and fusion (F) surface glycoproteins of hPIV3 are major antigenic determinants. Here we describe naturally occurring potently neutralizing human antibodies directed against both surface glycoproteins of hPIV3. We isolated seven neutralizing HN-reactive antibodies and a pre-fusion conformation F-reactive antibody from human memory B cells. One HN-binding monoclonal antibody (mAb), designated PIV3-23, exhibited functional attributes including haemagglutination and neuraminidase inhibition. We also delineated the structural basis of neutralization for two HN and one F mAbs. MAbs that neutralized hPIV3 in vitro protected against infection and disease in vivo in a cotton rat model of hPIV3 infection, suggesting correlates of protection for hPIV3 and the potential clinical utility of these mAbs.


Assuntos
Anticorpos Monoclonais , Anticorpos Neutralizantes , Anticorpos Antivirais , Proteína HN , Vírus da Parainfluenza 3 Humana , Infecções por Respirovirus , Sigmodontinae , Proteínas Virais de Fusão , Animais , Vírus da Parainfluenza 3 Humana/imunologia , Vírus da Parainfluenza 3 Humana/genética , Humanos , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/química , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/química , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/química , Proteínas Virais de Fusão/imunologia , Proteínas Virais de Fusão/química , Proteína HN/imunologia , Proteína HN/química , Proteína HN/genética , Infecções por Respirovirus/imunologia , Infecções por Respirovirus/virologia , Modelos Animais de Doenças , Testes de Neutralização , Linfócitos B/imunologia , Modelos Moleculares
5.
Nano Lett ; 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38781119

RESUMO

Although transition-metal nitrides have been widely applied for several decades, experimental investigations of their high-resolution electronic band structures are rare due to the lack of high-quality single-crystalline samples. Here, we report on the first momentum-resolved electronic band structures of titanium nitride (TiN) films, which are remarkable nitride superconductors. The measurements of the crystal structures and electrical transport properties confirmed the high quality of these films. More importantly, from a combination of high-resolution angle-resolved photoelectron spectroscopy and first-principles calculations, the extracted Coulomb interaction strength of TiN films can be as large as 8.5 eV, whereas resonant photoemission spectroscopy yields a value of 6.26 eV. These large values of Coulomb interaction strength indicate that superconducting TiN is a strongly correlated system. Our results uncover the unexpected electronic correlations in transition-metal nitrides, potentially providing a perspective not only to understand their emergent quantum states but also to develop their applications in quantum devices.

6.
Nano Lett ; 24(22): 6689-6695, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38781267

RESUMO

Highly ambitious initiatives aspire to propel a miniature spacecraft to a neighboring star within a human generation, leveraging the radiation pressure of lasers for propulsion. One major challenge for this enormous feat is to build a meter-scale, ultralow mass lightsail with broadband reflectivity. In this work, we present the design and fabrication of a lightsail composed of two distinct dielectric layers with photonic crystal/metasurface structure covering a 4" wafer. We achieved broadband reflection of >70% spanning over the full Doppler-shifted laser wavelength range during spacecraft acceleration with a low total mass in the range of a few grams when scaled up to meter size. Furthermore, we find new paths to reliably fabricate these subwavelength structures over macroscopic areas and then systematically characterize their optical performance, confirming their suitability for future lightsail applications. Our innovative device and precise nanofabrication approaches represent a significant leap toward interstellar exploration.

8.
Nat Commun ; 14(1): 4721, 2023 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-37543684

RESUMO

Preparing a massive mechanical resonator in a state with quantum limited motional energy provides a promising platform for studying fundamental physics with macroscopic systems and allows to realize a variety of applications, including precise sensing. While several demonstrations of such ground-state cooled systems have been achieved, in particular in sideband-resolved cavity optomechanics, for many systems overcoming the heating from the thermal bath remains a major challenge. In contrast, optomechanical systems in the sideband-unresolved limit are much easier to realize due to the relaxed requirements on their optical properties, and the possibility to use a feedback control schemes to reduce the motional energy. The achievable thermal occupation is ultimately limited by the correlation between the measurement precision and the back-action from the measurement. Here, we demonstrate measurement-based feedback cooling on a fully integrated optomechanical device fabricated using a pick-and-place method, operating in the deep sideband-unresolved limit. With the large optomechanical interaction and a low thermal decoherence rate, we achieve a minimal average phonon occupation of 0.76 when pre-cooled with liquid helium and 3.5 with liquid nitrogen. Significant sideband asymmetry for both bath temperatures verifies the quantum character of the mechanical motion. Our method and device are ideally suited for sensing applications directly operating at the quantum limit, greatly simplifying the operation of an optomechanical system in this regime.

9.
Nano Lett ; 23(12): 5673-5679, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37278509

RESUMO

The quantum anomalous Hall effect (QAHE) was discovered a decade ago but is still not utilized beyond a handful of research groups, due to numerous limitations such as extremely low temperature, electric-field-effect gating requirement, small sample sizes, and environmental aging effect. Here, we present a robust platform that provides effective solutions to these problems. Specifically, on this platform, we observe QAH signatures at record-high temperatures, with a Hall conductance of 1.00 e2/h at 2.0 K, 0.98 e2/h at 4.2 K, and 0.92 e2/h at 10 K, on centimeter-scale substrates, without electric-field-effect gating. The key ingredient is an active CrOx capping layer, which substantially boosts the ferromagnetism while suppressing environmental degradation. With this development, QAHE will now be accessible to much broader applications than before.

10.
Ecol Indic ; 150: 110221, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37265509

RESUMO

The global climate warming caused by urbanization has significantly affected the urban environment. Whilst land surface temperature (LST) is an important factor reflecting urban temperature, previous research on LST mostly focused on two-dimensional (2D) factors and rarely mentioned about the role of three-dimensional (3D) factors, particularly the LST variation characteristics of island cities. Therefore, this study examined the seasonal variation characteristics of urban LST by analyzing the impact of 2D and 3D urban morphology factors of different urban block types on LST in Xiamen Island. The main results are as follows. First, compact low layer (CL), a block type with a higher density of low-rise buildings, has a higher LST in any season. Under the same block density (BD), the higher the block average height (BH), the lower the LST. Second, among the 2D urban morphology factors, normalized difference vegetation index (NDVI) was the main factor for cities to reduce urban LST, especially in summer, while normalized difference built-up index (NDBI) was the opposite. Different from land cities, we found a positive correlation between modified normalized difference water body index (MNDWI) and LST in autumn and winter. Third, in the 3D urban morphology factors, sky view factor (SVF) was significantly positively correlated with LST, while building fluctuation (BF) was negatively correlated. The higher the SVF, the worse the radiation shielding effect between buildings. On the contrary, the higher the BF, the higher the building undulation, and the better the building radiation shielding. These findings should provide some quantitative insights for the future construction and planning of island cities, which can be used to improve the thermal environment of island cities and support the sustainable development of cities.

11.
Adv Mater ; 35(22): e2210940, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36921318

RESUMO

The interface between 2D topological Dirac states and an s-wave superconductor is expected to support Majorana-bound states (MBS) that can be used for quantum computing applications. Realizing these novel states of matter and their applications requires control over superconductivity and spin-orbit coupling to achieve spin-momentum-locked topological interface states (TIS) which are simultaneously superconducting. While signatures of MBS have been observed in the magnetic vortex cores of bulk FeTe0.55 Se0.45 , inhomogeneity and disorder from doping make these signatures unclear and inconsistent between vortices. Here superconductivity is reported in monolayer (ML) FeTe1-y Sey (Fe(Te,Se)) grown on Bi2 Te3 by molecular beam epitaxy (MBE). Spin and angle-resolved photoemission spectroscopy (SARPES) directly resolve the interfacial spin and electronic structure of Fe(Te,Se)/Bi2 Te3 heterostructures. For y = 0.25, the Fe(Te,Se) electronic structure is found to overlap with the Bi2 Te3 TIS and the desired spin-momentum locking is not observed. In contrast, for y = 0.1, reduced inhomogeneity measured by scanning tunneling microscopy (STM) and a smaller Fe(Te,Se) Fermi surface with clear spin-momentum locking in the topological states are found. Hence, it is demonstrated that the Fe(Te,Se)/Bi2 Te3 system is a highly tunable platform for realizing MBS where reduced doping can improve characteristics important for Majorana interrogation and potential applications.

12.
Mol Immunol ; 155: 58-68, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36709645

RESUMO

Radiation Pneumonitis (RP) is one of the most common and severe complication in patients receiving thoracic radiotherapy. The release of cytokines contribute to activating the RP process. Macrophages also play an important role in the pathogenesis of RP. The differential activation of macrophages is regulated by microRNA (miRNA). Exosomes containing miRNAs are one of the important ways to mediate cellular communication. However, the exosomes mediate communication between tumor cells and macrophages during the pathogenesis of RP remains understudied. In this study, we isolated and characterized the exosomes secreted by lung cancer cells after irradiation. Co-culture of exosomes with macrophages revealed that exosomes could induce macrophage proliferation activation and M2 polarization. miRNA array was used to analyze the differential expression of miRNAs in exosomes, and it was found that miR-4655-5p was stably and highly expressed in exosomes. The function of miR-4655-5p in macrophages was confirmed by overexpression/inhibition of miR-4655-5p expression in macrophages. The targeting association between miR-4655-5p and MID1 was determined by bioinformatics prediction followed by a confirmatory dual luciferase reporter assay. We showed that miR-4655-5p regulate the macrophage proliferation and inflammatory response by forming a negative regulatory loop that alters MID1 activity and its downstream PP2Ac. Overall, our results indicated that exosomal miR-4655-5p secreted by lung cancer cells after irradiation promoted the proliferation and M2 polarization of macrophages. It can be speculated that exosomes play an immunomodulatory role in the pathogenesis of RP and provided a new target for the prevention and treatment of RP.


Assuntos
Exossomos , Neoplasias Pulmonares , MicroRNAs , Humanos , Exossomos/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Macrófagos/metabolismo , Comunicação Celular , Neoplasias Pulmonares/patologia , Ubiquitina-Proteína Ligases/metabolismo
13.
RSC Adv ; 12(49): 31846-31854, 2022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36380954

RESUMO

We report a highly efficient nano-optical method for transforming a single yeast cell using exogenous genes. It used laser tweezers or micromanipulators to immobilize the cell immersed in a DNA solution and created a transient nano-sized hole on its cell wall concurrently with laser scissors to deliver nano moles of DNA into the cell. With this method, one can directly transfer the naked DNA of exogenous genes into yeast cells for transformation. We successfully transformed S. cerevisiae yeasts respectively with GFP (Green Fluorescent Protein) plasmid and the nucleic acid extraction of a bacteria GF1 from the gut of Coptotermes formosanus termites. The experimental results demonstrated that the recombinants had high survival rate and transformation efficiency (28%). The recombinant GFP-yeast system showed green fluorescence for generations. GF1 DNA sequences were incorporated into the yeast genome as a heritable component with stable expression for multi-generations so that the recombinant GF1-yeast had a strong capability of digesting biomass as GF1. Our method would apply to different cells with cell walls for various gene transformations.

14.
Nano Lett ; 22(18): 7522-7526, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36070237

RESUMO

Epitaxial Fe(Te,Se) thin films have been grown on various substrates but never been grown on magnetic layers. Here we report the epitaxial growth of fourfold Fe(Te,Se) film on a sixfold antiferromagnetic insulator, MnTe. The Fe(Te,Se)/MnTe heterostructure shows a clear superconducting transition at around 11 K, and the critical magnetic field measurement suggests the origin of the superconductivity to be bulk-like. Structural characterizations suggest that the uniaxial lattice match between Fe(Te,Se) and MnTe allows a hybrid symmetry epitaxy mode, which was recently discovered between Fe(Te,Se) and Bi2Te3. Furthermore, the Te/Fe flux ratio during deposition of the Fe(Te,Se) layer is found to be critical for its superconductivity. Now that superconducting Fe(Te,Se) can be grown on two related hexagonal platforms, Bi2Te3 and MnTe, this result opens a new possibility of combining topological superconductivity of Fe(Te,Se) with the rich physics in the intrinsic magnetic topological materials (MnTe)n(Bi2Te3)m family.

15.
Nano Lett ; 22(10): 4013-4019, 2022 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-35510870

RESUMO

We introduce a novel method to geometrically tune the tension in prestrained resonators by making Si3N4 strings with a designed predisplacement. This enables us, for example, to study their dissipation mechanisms, which are strongly dependent on the stress. After release of the resonators from the substrate, their static displacement is extracted using scanning electron microscopy. The results match finite-element simulations, which allows a quantitative determination of the resulting stress. The in- and out-of-plane eigenmodes are sensed using on-chip Mach-Zehnder interferometers, and the resonance frequencies and quality factors are extracted. The geometrically controlled stress enables tuning not only of the frequencies but also of the damping rate. We develop a model that quantitatively captures the stress dependence of the dissipation in the same SiN film. We show that the predisplacement shape provides additional flexibility, including control over the frequency ratio and the quality factor for a targeted frequency.


Assuntos
Compostos de Silício , Desenho de Equipamento , Microscopia Eletrônica de Varredura
16.
Environ Res ; 212(Pt D): 113442, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35588773

RESUMO

Bismuth-based materials are extensively studied for photocatalytic applications because of their unique crystal structure. Herein, we reported a binary graphene oxide (GO)/BiOCl composite material prepared by a hydrothermal method and analyzed its photodegradation mechanism through the semiconductor energy band theory. The degradation rate of the GO/BiOCl composite towards Rhodamine B could reach 93.6% within 8 min, and its performance exceeded that of most photocatalysts. The influencing factors for improving the photocatalytic activity are as follows: (1) abundant oxygen vacancies generated on the tight recombination interface; (2) a 2D-2D electron transfer channel between GO and BiOCl; and (3) GO acting as a load to provide more reaction sites for BiOCl nanosheets. This work provides a simple solution and theoretical explanation for the rapid degradation of pollutants, and has broad application prospects.

17.
IEEE J Biomed Health Inform ; 26(5): 2320-2330, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34910643

RESUMO

Saliva contains similar molecular components to serum. Analysis of saliva can provide important diagnostic information about the body. Here we report an artificial intelligence (AI) aided home-based method that can let pregnant women perform daily monitoring on their pregnant status and accurate prediction on their delivery date by the pattern analysis of their salivary crystals. The method was developed based on the information obtained from our investigation on the saliva samples of 170 pregnant women about the correlation of the salivary crystal pattern with pregnant age and fetal status. It demonstrated that the patterns of salivary crystallization could act as indicators of the pregnant age, fetal state, and some medical conditions of pregnant women. On this basis, with the aid of AI recognition and analysis of the fractal dimension and some characteristic crystals in the salivary crystallization, we performed estimation on the delivery date in both quantitative and qualitative manners. The accuracy of the prediction on 15 pregnant women was satisfactory: 100% delivering in the predicted week, 93.3% within the estimated three days, and 86.7% on the day as the prediction. We also developed a simple smartphone-based AI-aided salivary crystal imaging and analysis device as an auxiliary means to let pregnant women monitor their fetal status daily at home and predict their delivery date with adequate accuracy.


Assuntos
Gestantes , Saliva , Inteligência Artificial , Cristalização , Feminino , Feto , Humanos , Gravidez , Saliva/química
18.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-933614

RESUMO

Objective:To investigate the clinical result of biological mesh and synthetic mesh in the repair of hiatal hernia.Methods:a prospective cohort study was conducted to collect and analyze the clinical data of 60 patients with hiatal hernia who were treated at Department of Hernia and Abdominal Wall Surgery, Beijing Chaoyang Hospital, Capital Medical University from May 2019 to Jan 2020. Intraoperative blood loss, hospital stay, clinical symptoms (heartburn, acid regurgitation, belching, early satiety, chest pain), VAS score, postoperative recurrence rate and complications were evaluated.Results:There was no significant difference in the overall repair effect between biological mesh group and synthetic mesh group ( P>0.05). All of the 60 patients underwent successful laparoscopic hiatal hernia repair and fundoplication. There were no massive bleeding caused by organ or vascular injury, and no peri-operative death. No recurrence of hiatal hernia, massive hemorrhage, pneumothorax, pleural effusion, gastrointestinal fistula, mediastinal infection or abscess were found during the follow-up of 6 months. Conclusion:There is no significant difference in short-term clinical effect between the use of biological mesh and synthetic mesh after hiatal hernia repair.

19.
Rev Cardiovasc Med ; 23(11): 360, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39076186

RESUMO

Background: Dual antiplatelet therapy (DAPT) with potent P2Y12 inhibitor is the cornerstone of acute coronary syndrome (ACS) management. Balancing the effects of different strategies of antiplatelet therapy including DAPT de-escalation, potent P2Y12 inhibitor monotherapy, and conventional DAPT is a hot topic. Methods: A systematic search was conducted from the MEDLINE, PubMed, and Embase through October 2021 to identify various DAPT strategies in randomized controlled trials (RCTs) for treatment of ACS patients after undergoing PCI with drug-eluting stent (DES). The network meta-analysis was performed to investigate the net clinic benefit of the DAPT de-escalation, potent P2Y12 inhibitor monotherapy, as well as conventional DAPT. The primary outcome was net adverse clinical events, defined as a composite of major bleeding and cardiac death, myocardial infarction, stroke, stent thrombosis, or target-vessel revascularization. The secondary outcomes include major adverse cardiac events and trial-defined major or minor bleeding. Results: A total of 14 RCTs with 63,982 patients were included. The DAPT de-escalation was associated with a lower risk of the primary outcome compared with potent P2Y12 inhibitor monotherapy (De-escalation vs monotherapy odds ratio (OR): 0.72 95% confidence interval (CI): 0.55-0.96), and other antiplatelet strategies (De-escalation vs clopidogrel + aspirin OR: 0.49 95% CI: 0.39-0.63; De-escalation vs prasugrel + aspirin OR: 0.76 95% CI: 0.59-0.98; De-escalation vs ticagrelor + aspirin OR: 0.76 95% CI: 0.55-0.90). There were no statistical differences in the incidence of bleeding (DAPT de-escalation vs P2Y12 inhibitor monotherapy OR: 0.73 95% CI: 0.47-1.12) and major adverse cardiac events (DAPT de-escalation vs P2Y12 inhibitor monotherapy OR: 0.79 95% CI: 0.59-1.08) between DAPT de-escalation and potent P2Y12 inhibitor monotherapy. Conclusions: This network meta-analysis showed that DAPT de-escalation would reduce the net adverse clinical events, compared with potent P2Y12 inhibitor monotherapy, for ACS patients undergone PCI treatment.

20.
Nano Lett ; 21(14): 5914-5919, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34265206

RESUMO

Controlling magnetic order in magnetic topological insulators (MTIs) is a key to developing spintronic applications with MTIs and is commonly achieved by changing the magnetic doping concentration, which inevitably affects the spin-orbit coupling strength and the topological properties. Here, we demonstrate tunable magnetic properties in topological heterostructures over a wide range, from a ferromagnetic phase with a Curie temperature of around 100 K all the way to a paramagnetic phase, while keeping the overall chemical composition the same, by controlling the thickness of nonmagnetic spacer layers between two atomically thin magnetic layers. This work showcases that spacer-layer control is a powerful tool to manipulate magneto-topological functionalities in MTI heterostructures. Furthermore, the interaction between the MTI and the Cr2O3 buffer layers also leads to a robust topological Hall effect surviving up to a record-high 6 T of magnetic field, shedding light on the critical role of interfacial layers in thin-film topological materials.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA