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1.
Proc Natl Acad Sci U S A ; 121(27): e2406884121, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38935562

RESUMO

Degeneracy and symmetry have a profound relation in quantum systems. Here, we report gate-tunable subband degeneracy in PbTe nanowires with a nearly symmetric cross-sectional shape. The degeneracy is revealed in electron transport by the absence of a quantized plateau. Utilizing a dual gate design, we can apply an electric field to lift the degeneracy, reflected as emergence of the plateau. This degeneracy and its tunable lifting were challenging to observe in previous nanowire experiments, possibly due to disorder. Numerical simulations can qualitatively capture our observation, shedding light on device parameters for future applications.

2.
Mol Psychiatry ; 29(5): 1417-1426, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38278992

RESUMO

Human genetic studies indicate that suicidal ideation and behavior are both heritable. Most studies have examined associations between aberrant gene expression and suicide behavior, but behavior risk is linked to the severity of suicidal ideation. Through a gene network approach, this study investigates how gene co-expression patterns are associated with suicidal ideation and severity using RNA-seq data in peripheral blood from 46 live participants with elevated suicidal ideation and 46 with no ideation. Associations with the presence of suicidal ideation were found within 18 co-expressed modules (p < 0.05), as well as in 3 co-expressed modules associated with suicidal ideation severity (p < 0.05, not explained by severity of depression). Suicidal ideation presence and severity-related gene modules with enrichment of genes involved in defense against microbial infection, inflammation, and adaptive immune response were identified and investigated using RNA-seq data from postmortem brain that revealed gene expression differences with moderate effect sizes in suicide decedents vs. non-suicides in white matter, but not gray matter. Findings support a role of brain and peripheral blood inflammation in suicide risk, showing that suicidal ideation presence and severity are associated with an inflammatory signature detectable in blood and brain, indicating a biological continuity between ideation and suicidal behavior that may underlie a common heritability.


Assuntos
Encéfalo , Ideação Suicida , Suicídio , Transcriptoma , Humanos , Feminino , Masculino , Transcriptoma/genética , Suicídio/psicologia , Adulto , Encéfalo/metabolismo , Pessoa de Meia-Idade , Redes Reguladoras de Genes/genética , Depressão/genética , Depressão/sangue , Inflamação/genética , Inflamação/sangue
3.
Nano Lett ; 24(15): 4658-4664, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38563608

RESUMO

Planar Josephson junctions are predicted to host Majorana zero modes. The material platforms in previous studies are two-dimensional electron gases (InAs, InSb, InAsSb, and HgTe) coupled to a superconductor such as Al or Nb. Here, we introduce a new material platform for planar JJs, the PbTe-Pb hybrid. The semiconductor, PbTe, was grown as a thin film via selective area epitaxy. The Josephson junction was defined by a shadow wall during the deposition of superconductor Pb. Scanning transmission electron microscopy reveals a sharp semiconductor-superconductor interface. Gate-tunable supercurrents and multiple Andreev reflections are observed. A perpendicular magnetic field causes interference patterns of the switching current, exhibiting Fraunhofer-like and SQUID-like behaviors. We further demonstrate a prototype device for Majorana detection wherein phase bias and tunneling spectroscopy are applicable.

4.
Phys Chem Chem Phys ; 26(14): 11037-11047, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38526740

RESUMO

Electrochemical CO2 transformation to fuels and chemicals is an effective strategy for conversion of renewable electric energy into storable chemical energy in combination with reducing green-house gas emission. Metal-nitrogen-carbon (M-N-C) single atom catalysts (SAC) have shown great potential in the electrochemical CO2 reduction reaction (CO2RR). However, exploring advanced SACs with simultaneously high catalytic activity and high product selectivity remains a great challenge. In this study, density functional theory (DFT) calculations are combined with machine learning (ML) for rapid and high-throughput screening of high performance CO reduction catalysts. Firstly, the electrochemical properties of 99 M-N-C SACs were calculated by DFT and used as a database. By using different machine learning models with simple features, the investigated SACs were expanded from 99 to 297. Through several effective indicators of catalyst stability, inhibition of the hydrogen evolution reaction, and CO adsorption strength, 33 SACs were finally selected. The catalytic activity and selectivity of the remaining 33 SACs were explored by micro-kinetic simulation based on Marcus theory. Among all the studied SACs, Mn-NC2, Pt-NC2, and Au-NC2 deliver the best catalytic performance and can be used as potential catalysts for CO2/CO conversion to hydrocarbons with high energy density. This effective screening method using a machine learning algorithm can promote the exploration of CO2RR catalysts and significantly reduce the simulation cost.

5.
Mol Cell ; 63(5): 781-95, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27588602

RESUMO

Mutations in the human autophagy gene EPG5 cause the multisystem disorder Vici syndrome. Here we demonstrated that EPG5 is a Rab7 effector that determines the fusion specificity of autophagosomes with late endosomes/lysosomes. EPG5 is recruited to late endosomes/lysosomes by direct interaction with Rab7 and the late endosomal/lysosomal R-SNARE VAMP7/8. EPG5 also binds to LC3/LGG-1 (mammalian and C. elegans Atg8 homolog, respectively) and to assembled STX17-SNAP29 Qabc SNARE complexes on autophagosomes. EPG5 stabilizes and facilitates the assembly of STX17-SNAP29-VAMP7/8 trans-SNARE complexes, and promotes STX17-SNAP29-VAMP7-mediated fusion of reconstituted proteoliposomes. Loss of EPG5 activity causes abnormal fusion of autophagosomes with various endocytic vesicles, in part due to elevated assembly of STX17-SNAP25-VAMP8 complexes. SNAP25 knockdown partially suppresses the autophagy defect caused by EPG5 depletion. Our study reveals that EPG5 is a Rab7 effector involved in autophagosome maturation, providing insight into the molecular mechanism underlying Vici syndrome.


Assuntos
Agenesia do Corpo Caloso/genética , Autofagossomos/metabolismo , Catarata/genética , Endossomos/metabolismo , Lisossomos/metabolismo , Proteínas/genética , Proteínas rab de Ligação ao GTP/genética , Agenesia do Corpo Caloso/metabolismo , Agenesia do Corpo Caloso/patologia , Sequência de Aminoácidos , Animais , Autofagossomos/ultraestrutura , Autofagia/genética , Proteínas Relacionadas à Autofagia , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Catarata/metabolismo , Catarata/patologia , Endossomos/ultraestrutura , Regulação da Expressão Gênica , Células HeLa , Humanos , Proteínas de Membrana Lisossomal , Lisossomos/ultraestrutura , Fusão de Membrana , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Ligação Proteica , Proteínas/metabolismo , Proteínas Qa-SNARE/genética , Proteínas Qa-SNARE/metabolismo , Proteínas Qb-SNARE/genética , Proteínas Qb-SNARE/metabolismo , Proteínas Qc-SNARE/genética , Proteínas Qc-SNARE/metabolismo , Proteínas R-SNARE/genética , Proteínas R-SNARE/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Proteína 25 Associada a Sinaptossoma/genética , Proteína 25 Associada a Sinaptossoma/metabolismo , Proteínas de Transporte Vesicular , Proteínas rab de Ligação ao GTP/metabolismo , proteínas de unión al GTP Rab7
6.
Oral Dis ; 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38376115

RESUMO

OBJECTIVES: To investigate the inhibitory effects of STM2457, which is a novel METTL3 (m6 A writer) inhibitor, both as a monotherapy and in combination with anlotinib, in the treatment of oral squamous cell carcinoma (OSCC) both in vitro and in vivo. MATERIALS AND METHODS: The efficacy of STM2457 or STM2457 plus anlotinib was evaluated using two OSCC cell lines by CCK8, transwell, colony formation, would-healing, sphere formation, cell cycle, apoptosis assays, and nude mice tumor xenograft techniques. The molecular mechanism study was carried out by western blotting, qRT-PCR, MeRIP-qPCR, immunofluorescence, and immunohistochemistry. RESULTS: STM2457 combined with anlotinib enhanced inhibition of cellular survival/proliferation and promotion of apoptosis in vitro. Moreover, this combinatorial approach exerted a notable reduction in stemness properties and EMT (epithelial-mesenchymal transition) features of OSCC cells. Remarkably, in vivo studies validated the efficacy of the combination treatment. Mechanistically, our investigations revealed that the combined action of STM2457 and anlotinib exerted downregulatory effects on EGFR (epidermal growth factor receptor) expression in OSCC cells. CONCLUSIONS: The combination of STM2457 and anlotinib targeting EGFR exerted a multiple anti-tumor effect. In near future, anlotinib combined with STM2457 may provide a novel insight for the treatment of OSCC.

7.
Sensors (Basel) ; 24(2)2024 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-38276369

RESUMO

We introduced a label-free sensing system based on an array of microring resonators (MRRs) which was successfully employed for human serum albumin (HSA) detection. The sensing-ring surface was functionalized to immobilize anti-HSA, facilitating HSA binding. Our refractive index sensing system demonstrates high sensitivity at 168 nm/RIU and a low limit of detection (LOD) of 63.54 ng/mL, closely comparable to current HSA detection methods. These findings confirm the potential of MRRs as biocompatible sensors for HSA detection. This system holds great promise as an innovative platform for the detection of HSA, carrying significant importance in medical diagnostics.


Assuntos
Técnicas Biossensoriais , Refratometria , Humanos , Limite de Detecção
8.
Nano Lett ; 23(23): 11137-11144, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-37948302

RESUMO

Disorder is the primary obstacle in the current Majorana nanowire experiments. Reducing disorder or achieving ballistic transport is thus of paramount importance. In clean and ballistic nanowire devices, quantized conductance is expected, with plateau quality serving as a benchmark for disorder assessment. Here, we introduce ballistic PbTe nanowire devices grown by using the selective-area-growth (SAG) technique. Quantized conductance plateaus in units of 2e2/h are observed at zero magnetic field. This observation represents an advancement in diminishing disorder within SAG nanowires as most of the previously studied SAG nanowires (InSb or InAs) have not exhibited zero-field ballistic transport. Notably, the plateau values indicate that the ubiquitous valley degeneracy in PbTe is lifted in nanowire devices. This degeneracy lifting addresses an additional concern in the pursuit of Majorana realization. Moreover, these ballistic PbTe nanowires may enable the search for clean signatures of the spin-orbit helical gap in future devices.

9.
Int J Mol Sci ; 25(6)2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38542520

RESUMO

Injuries and subclinical effects from exposure to blasts are of significant concern in military operational settings, including tactical training, and are associated with self-reported concussion-like symptomology and physiological changes such as increased intestinal permeability (IP), which was investigated in this study. Time-series gene expression and IP biomarker data were generated from "breachers" exposed to controlled, low-level explosive blast during training. Samples from 30 male participants at pre-, post-, and follow-up blast exposure the next day were assayed via RNA-seq and ELISA. A battery of symptom data was also collected at each of these time points that acutely showed elevated symptom reporting related to headache, concentration, dizziness, and taking longer to think, dissipating ~16 h following blast exposure. Evidence for bacterial translocation into circulation following blast exposure was detected by significant stepwise increase in microbial diversity (measured via alpha-diversity p = 0.049). Alterations in levels of IP protein biomarkers (i.e., Zonulin, LBP, Claudin-3, I-FABP) assessed in a subset of these participants (n = 23) further evidenced blast exposure associates with IP. The observed symptom profile was consistent with mild traumatic brain injury and was further associated with changes in bacterial translocation and intestinal permeability, suggesting that IP may be linked to a decrease in cognitive functioning. These preliminary findings show for the first time within real-world military operational settings that exposures to blast can contribute to IP.


Assuntos
Traumatismos por Explosões , Concussão Encefálica , Militares , Humanos , Masculino , Militares/psicologia , Função da Barreira Intestinal , Traumatismos por Explosões/complicações , Concussão Encefálica/complicações , Biomarcadores
10.
J Child Lang ; : 1-26, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38497445

RESUMO

This study investigated differences in adult-child language interactions when parents and their three-to-four-year old children engage in wordless book reading, text-and-picture book reading and a small-world toy play activity. Twenty-two parents recorded themselves completing each activity at home with their child. Parent input was compared across contexts, focusing on interactive and conceptual domains: use of open prompts, expansions or extensions of children's utterances, and use of decontextualised (abstract) language. Use of linguistic expansions was greater during book reading than toy play. Parents used open questions and added contingent conceptual information more often when reading wordless books than in both other conditions. Findings suggest that wordless books may combine the benefits of open-endedness and linguistic content based around a narrative. Parents' use of abstract language also varied by condition. This study extends understanding of the role of activity context in shaping children's language learning environments.

11.
Angew Chem Int Ed Engl ; 63(8): e202315841, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38179848

RESUMO

Inherent "soft" ionic lattice nature of halide perovskite quantum dots (QDs), triggered by the weak Pb-X (X=Cl, Br, I) bond, is recognized as the primary culprit for their serious instability. A promising way is to construct exceedingly strong ionic interaction inside the QDs and increase their crystal cohesive energy by substituting the interior X- with highly electronegative F- , however, which is challenging and hitherto remains unreported. Here, a "whole-body" fluorination strategy is proposed for strengthening the interior bonding architecture of QDs, wherein the F- are uniformly distributed throughout the whole nanocrystal encompassing both the interior lattice and surface, successfully stabilizing their "soft" crystal lattice and passivating surface defects. This approach effectively mitigates their intrinsic instability issues including light-induced phase segregation. As a result, light-emitting devices based on these QDs exhibit exceptional efficiency and remarkable stability.

12.
Anal Chem ; 95(51): 18859-18870, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38096265

RESUMO

Trivalent Au ions are easily reduced to be zerovalent atoms by coexisting reductant reagents, resulting in the subsequent accumulation of Au atoms and formation of plasmonic nanostructures. In the absence of stabilizers or presence of weak stabilizers, aggregative growth of Au nanoparticles (NPs) always occurs, and unregular multidimensional Au materials are consequently constructed. Herein, the addition of nanomole-level mercury ions can efficiently prevent the epitaxial accumulation of Au atoms, and separated Au NPs with mediated morphologies and superior plasmonic characteristics are obtained. Experimental results and theoretical simulation demonstrate the Hg-concentration-reliant formation of plasmonic nanostructures with their mediated sizes and shapes in the presence of weak reductants. Moreover, the sensitive plasmonic responses of reaction systems exhibit selectivity comparable to that of Hg species. As a concept of proof, polymeric carbon dots (CDs) were used as the initial reductant, and the reactions between trivalent Au and CDs were studies. Significantly, Hg atoms prevent the epitaxial accumulation of Au atoms, and plasmonic NPs with decreased sizes were in situ synthesized, corresponding to varied surface plasmonic resonance absorption performance of the CD-induced hybrids. Moreover, with the integration of sensing substrates of CD-doped hydrogels, superior response stabilities, analysis selectivity, and sensitivity of Hg2+ ions were achieved on the basis of the mercury-mediated in situ chemical reactions between trivalent Au ions and reductant CDs. Consequently, a high-performance sensing strategy with the use of Au NP-staining hydrogels (nanostaining hydrogels) was exhibited. In addition to Hg sensing, the nanostaining hydrogels facilitated by doping of emerging materials and advanced chem/biostrategies can be developed as high-performance on-site monitoring routes to various pollutant species.

13.
Inorg Chem ; 62(17): 6794-6807, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37074172

RESUMO

Intimate interface design at the molecular level in heterojunctions deserves significant attention since the charge transfer efficiency at the interfaces can greatly affect the catalytic performance. Herein, an efficient interface engineering strategy was reported to design a titanium porphyrin metal-organic framework-ZnIn2S4 (TMF-ZIS) core-shell heterojunction which is tightly connected via coordination bonds (-N-Zn-). Such interfacial chemical bonds as the directional carrier transfer channels afforded improved charge separation efficiency compared to the physical composite of TMF and ZIS without chemical bonding. As a result, the optimized TMF-ZIS composite showed a 13.37 mmol·g-1·h-1 H2 production which is 47.7, 3.3, and 2.4 times that of TMF, ZIS, and mechanical mixing samples, respectively. Moreover, the composite also exhibited high photocatalytic tetracycline hydrochloride (TCH) degradation efficiency. Profiting from the core-shell structures, the ZIS shell efficiently prevented the aggregation and photocorrosion of TMF core particles which afforded enhanced chemical stability. Such an interface engineering strategy will be a versatile method to obtain highly effective organic-inorganic heterojunctions and offer new ideas for modulating the interfaces in the heterojunctions at the molecular level.

14.
BMC Pregnancy Childbirth ; 23(1): 569, 2023 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-37550654

RESUMO

BACKGROUND: To develop an ultrasound scoring system for placenta accreta spectrum (PAS), evaluate its diagnostic value, and provide a practical approach to prenatal diagnosis of PAS. METHODS: A total of 532 pregnant women (n = 184 no PAS, n = 120 placenta accreta, n = 189 placenta increta, n = 39 placenta percreta) at high-risk for placenta accreta who delivered in the Third Affiliated Hospital of Zhengzhou University between January 2021 and December 2022 underwent prenatal ultrasound to evaluate placental invasion. An ultrasound scoring system that included placental and cervical morphology and history of cesarean section was created. Each feature was assigned a score of 0 ~ 2, according to severity. Thresholds for the total ultrasound score that discriminated between no PAS, placenta accreta, placenta increta, and placenta percreta were calculated. RESULTS: Univariate and multivariate regression analysis identified seven indicators of PAS that were included in the ultrasound scoring system, including placental location, placental thickness, presence/absence of the retroplacental space, thickness of the retroplacental myometrium, presence/absence of placental lacunae, retroplacental myometrial blood flow and history of cesarean section. Using the final ultrasound scoring system, no PAS is diagnosed at a total score < 5, placenta accreta or placenta increta is diagnosed at a total score 5-10, and placenta percreta is diagnosed at a total score ≥ 10. CONCLUSIONS: This study identified seven indicators of PAS and included them in an ultrasound scoring system that has good diagnostic efficacy and clinical utility. TRIAL REGISTRATION: ChiCTR2300069261 (retrospectively registered on 10/03/2023).


Assuntos
Placenta Acreta , Placenta Prévia , Feminino , Gravidez , Humanos , Placenta Acreta/diagnóstico por imagem , Placenta/diagnóstico por imagem , Cesárea , Ultrassonografia Pré-Natal , Diagnóstico Pré-Natal , Placenta Prévia/diagnóstico por imagem , Estudos Retrospectivos
15.
Plant Dis ; 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36916847

RESUMO

Red clover (Trifolium pratense) is becoming increasingly important in grassland systems (sheep and beef) due to its high productivity, protein content and nitrogen-fixing ability which allows lower N fertilizer use (Murray et al. 2007). In June 2021, an unidentified foliar disease occurred seriously in experimental fields of red clover (25.61°N, 102.48°E) in Kunming city, Yunnan Province, China. Disease incidence was approximately 55% with an average disease severity of 41.1% in the fields (about 1.5 ha). Initially, the symptoms consisted of cicular to oval leaf spots with dark brown edges. In severely diseased plots, the diseased spots continued to expand and fuse along the leaf veins, forming long and narrow leaf spots, and the middle of the leaves were decayed and hollow. To isolate the pathogen, small pieces (3×3 mm) from the margin of infected lesions were surface-sterilized in 75% ethanol solution for 30 s, 1% NaClO solution for 90 s, rinsed three times with sterilized distilled water, air dried, and plated onto potato dextrose agar (PDA). The same fungus was isolated in 90% of the samples and purified by transferring the hyphal tip from the edge of colonies to fresh PDA plates. The colonies produced relatively dense light-grayish aerial mycelium in the early stage, which turned grayish upon mature, and then dark brown on the back of the colonies with dense small black patches. Conidiophores were unbranched, straight or flexuous, accompanied by slight or obvious swelling of its apical cells. Conidia were olive brown, irregularly round, 1 to 3 transverse septa, 0 to 2 longitudinal or oblique septa, and measured 16.0 - (24.8)- 30.1 × 13.9 - (21.4) - 28.6 µm (n = 50). Morphological characteristics were consistent with those described for Stemphylium vesicarium (Simmons, 1967). For molecular identification, total genomic DNA was isolated from mycelia collected from 6 day-old colonies of three representative isolates LZQF-1-LZQF-3 using the Omega D3195 fungal genomic DNA extraction kit. Fragments of three genes, including those encoding the ITS region of rDNA, calmodulin gene (cmdA), and glyceraldehyde-3-phosphate dehydrogenase (gpd) regions of isolates LZQF-1-LZQF-3 were amplified by the primers described previously (Woudenberg et al. 2017) and sequenced. Resulting sequences of representative strain LZQF-1 were deposited in GenBank with accession numbers of OL615093 (ITS), OL624541 (cmdA) and OL624538 (gpd), respectively. A nucleotide BLAST search revealed ITS, cmdA and gpd sequences to be 100%, 100% and 99.0% similar to the corresponding sequences (accessions numbers KU850563.1, KU850853.1 and KU850710.1) of ex-type strain CBS 370.51 of S. vesicarium. The three locus datasets were combined by SequenceMatrix 1.8 (Vaidya et al. 2011), and the strain LZQF-1-LZQF-3 and S. vesicarium (CBS 192.86, CBS 370.51 and CBS 205.82) formed a subclade with 99% bootstrap support. Pathogenicity tests were performed on LZQF-1 in a greenhouse at 18 °C-26 °C with 75% relative humidity. Three pots each containing three 50-day-old red clover were sprayed with the conidial suspension (3 × 105 conidia/ml) while another three pots were sprayed with sterile water as a control. Two weeks later, the inoculated leaves showed oval leaf spots with dark brown edges, distinctive symptoms of S. vesicarium infection. S. vesicarium was reisolated and confirmed by morphological and molecular features. There were no symptoms on the control leaves. S. vesicarium as a pathogen causing leaf spot disease has been reported on red clover in Canada (Jasalavich et al. 1995) and in Russia (Babuschkina et al. 1995). To our knowledge, this is the first report of leaf spot of red clover caused by S. vesicarium in China. The identification of Stemphylium leaf spot lays the groundwork for future investigations into epidemiology and management of S. vesicarium on red clover.

16.
Nano Lett ; 22(13): 5538-5543, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35766622

RESUMO

Ferrofluids (FFs) can adapt their shape to a magnetic field. However, they cannot maintain their shape when the magnetic field is removed. Here, with a magneto-responsive and reconfigurable interfacial self-assembly (MRRIS) process, we show that FFs can be structured by a magnetic field and maintain their shape, like solids, after removing the magnetic field. The competing self-assembly of magnetic and nonmagnetic nanoparticles at the liquid interface endow FFs with both reconfigurability and structural stability. By manipulating the external magnetic field, we show that it is possible to "write" and "erase" the shape of the FFs remotely and repeatedly. To gain an in-depth understanding of the effect of MRRIS on the structure of FFs, we systematically study the shape variation of these liquids under both the static and dynamic magnetic fields. Our study provides a simple yet novel way of manipulating FFs and opens opportunities for the fabrication of all-liquid devices.


Assuntos
Coloides , Nanopartículas , Coloides/química , Campos Magnéticos , Magnetismo , Nanopartículas/química
17.
Angew Chem Int Ed Engl ; 62(18): e202301684, 2023 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-36867124

RESUMO

Exciton localization is an approach for preparing highly luminescent semiconductors. However, realizing strongly localized excitonic recombination in low-dimensional materials such as two-dimensional (2D) perovskites remains challenging. Herein, we first propose a simple and efficient Sn2+ vacancy (VSn ) tuning strategy to enhance excitonic localization in 2D (OA)2 SnI4 (OA=octylammonium) perovskite nanosheets (PNSs), increasing their photoluminescence quantum yield (PLQY) to ≈64 %, which is among the highest values reported for tin iodide perovskites. Combining experimental with first-principles calculation results, we confirm that the significantly increased PLQY of (OA)2 SnI4 PNSs is primarily due to self-trapped excitons with highly localized energy states induced by VSn . Moreover, this universal strategy can be applied for improving other 2D Sn-based perovskites, thereby paving a new way to fabricate diverse 2D lead-free perovskites with desirable PL properties.

18.
Angew Chem Int Ed Engl ; 62(24): e202301564, 2023 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-37026975

RESUMO

Dynamic room temperature phosphorescence (RTP) materials have potential applications in optoelectronics, which inevitably suffer from poor processability, flexibility or stretchability. Herein, we report a concise strategy to develop supercooled liquids (SCLs) with dynamic RTP behavior using terminal hydroxyl engineering. The terminal hydroxyls effectively hinder the nucleation process of molecules for the formation of stable SCLs after thermal annealing. Impressively, the SCLs show reversible RTP emission via alternant stimulation by UV light and heat. Photoactivated SCLs have phosphorescent efficiency of 8.50 % and a lifetime of 31.54 ms under ambient conditions. Regarding the dynamic RTP behavior and stretchability of SCLs, we demonstrate the applications in erasable data encryption and patterns on flexible substrates. This finding provides a design principle for obtaining SCLs with RTP and expands the potential applications of RTP materials in flexible optoelectronics.

19.
Small ; 18(24): e2201311, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35561067

RESUMO

Deficiencies in understanding the local environment of active sites and limited synthetic skills challenge the delivery of industrially-relevant current densities with low overpotentials and high selectivity for CO2 reduction. Here, a transient laser induction of metal salts can stimulate extreme conditions and rapid kinetics to produce defect-rich indium nanoparticles (L-In) is reported. Atomic-resolution microscopy and X-ray absorption disclose the highly defective and undercoordinated local environment in L-In. In a flow cell, L-In shows a very small onset overpotential of ≈92 mV and delivers a current density of ≈360 mA cm-2 with a formate Faradaic efficiency of 98% at a low potential of -0.62 V versus RHE. The formation rate of formate reaches up to 6364.4 µmol h-1mgIn-1$mg_{{\rm{In}}}^{--1}$ , which is nearly 39 folds higher than that of commercial In (160.7 µmol h-1mgIn-1$mg_{{\rm{In}}}^{--1}$ ), outperforming most of the previous results that have been reported under KHCO3 environments. Density function theory calculations suggest that the defects facilitate the formation of *OCHO intermediate and stabilize the *HCOOH while inhibiting hydrogen adsorption. This study suggests that transient solid-state laser induction provides a facile and cost-effective approach to form ligand-free and defect-rich materials with tailored activities.


Assuntos
Índio , Lasers de Estado Sólido , Dióxido de Carbono/química , Formiatos/química
20.
Phys Rev Lett ; 129(16): 167702, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36306766

RESUMO

Probing an isolated Majorana zero mode is predicted to reveal a tunneling conductance quantized at 2e^{2}/h at zero temperature. Experimentally, a zero-bias peak (ZBP) is expected and its height should remain robust against relevant parameter tuning, forming a quantized plateau. Here, we report the observation of large ZBPs in a thin InAs-Al hybrid nanowire device. The ZBP height can stick close to 2e^{2}/h, mostly within 5% tolerance, by sweeping gate voltages and magnetic field. We further map out the phase diagram and identify two plateau regions in the phase space. Despite the presence of disorder and quantum dots, our result constitutes a step forward toward establishing Majorana zero modes.

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