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1.
Cancer Cell Int ; 24(1): 83, 2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38402402

RESUMO

Apatinib was the first anti-angiogenic agent approved for treatment of metastatic gastric cancer (GC). However, the emergence of resistance was inevitable. Thus investigating new and valuable off-target effect of apatinib directly against cancer cells is of great significance. Here, we identified extra spindle pole bodies-like 1 (ESPL1) was responsible for apatinib resistance in GC cells through CRISPR genome-wide gain-of-function screening. Loss of function studies further showed that ESPL1 inhibition suppressed cell proliferation, migration and promoted apoptosis in vitro, and accordingly ESPL1 knockdown sensitized GC cells to apatinib. In addition, we found ESPL1 interacted with mouse double minute 2 (MDM2), a E3 ubiquitin protein ligase, and the combination of MDM2 siRNA with apatinib synergistically ameliorated the resistance induced by ESPL1 overexpression. In summary, our study indicated that ESPL1 played a critical role in apatinib resistance in GC cells. Inhibition of MDM2 could rescue the sensitivity of GC cells to apatinib and reverse ESPL1-mediated resistance.

2.
Chemistry ; : e202402806, 2024 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-39180461

RESUMO

Tunable luminescence-assisted information storage and encryption holds increasing significance in today's society. A promising approach to incorporating the benefits of both organic long persistent luminescent (LPL) materials and rare-earth (RE) luminescence lies in utilizing organic host materials to sensitize RE luminescence, as well as hydrogen-bonded organic framework (HOF) phosphorescence Förster resonance energy transfer to RE compound luminescence. This work introduces a one-pot, in situ pyrolytic condensation method, achieved through high-temperature melting calcination, to synthesize lanthanide ion-doped HOF materials. This method circumvents the drawback of molecular triplet energy annihilation, enabling the creation of organic LPL materials with RE characteristics. The HOF material serves as the host, exhibiting blue phosphorescence and cyan LPL. By fine-tuning the doping amount, the composite material U-Tb-100 achieves green LPL with a luminescent quantum yield of 56.4%, and an LPL duration of approximately 2-3 s, demonstrating tunable persistence. Single-crystal X-ray diffraction, spectral analysis, and theoretical calculation unveil that U-Tb-100 exhibits exceptional quantum yield and long-lived luminescence primarily due to the efficient sensitization of U monomer to RE ions and the PRET process between U and RE complexes. This ingenious strategy not only expands the repertoire of HOF materials but also facilitates the design of multifunctional LPL materials.

3.
Inorg Chem ; 63(2): 1188-1196, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38175718

RESUMO

Metal-organic frameworks (MOFs) with long persistent luminescence (LPL) have attracted extensive research attention from researchers due to their potential applications in information encryption, anticounterfeiting technology, and security logic. In contrast to short-lived fluorescent materials, LPL materials offer a visible response that can be easily distinguished by the naked eye, thereby facilitating a much clearer visualization. However, there are few reports on functional LPL MOF materials as probes. In this article, two amino-functional LPL MOFs (VB4-2D and VB4-1D) were synthesized. They both exhibited adjustable fluorescence and phosphorescence from blue to green and from cyan to green, respectively. Notably, the MOFs emitted bright and adjustable LPL upon the removal of the different radiation sources. The basic amino functional groups in the MOFs exhibited acid and ammonia sensitivity, and fluorescence and phosphorescence emission intensities can be burst and restored in two atmospheres, respectively, which can be cycled multiple times. Furthermore, LPL intensity undergoes switching between two different conditions as well, which can be visually discerned by the naked eye, enabling visual sensing of volatiles by LPL. This combination of photoluminescence and the visual LPL switching behavior of acids and bases in functional MOFs may provide an effective avenue for stimulus response, anticounterfeiting, and encryption applications.

4.
Bioorg Med Chem ; 111: 117869, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39126834

RESUMO

Recently, the sortilin receptor (SORT1) was found to be preferentially over-expressed on the surface of many cancer cells, which makes SORT1 a novel anticancer target. The SORT1 binding proprietary peptide TH19P01 could achieve the SORT1-mediated cancer cell binding and subsequent internalization. Inspired by the peptide-drug conjugate (PDC) strategy, the TH19P01-camptothecin (CPT) conjugates were designed, efficiently synthesized, and evaluated for their anticancer potential in this study. The water solubility, in vitro anticancer activity, time-kill kinetics, cellular uptake, anti-migration activity, and hemolysis effects were systematically estimated. Besides, in order to monitor the release of CPT from conjugates in real-time, the CPT/Dnp-based "turn on" hybrid peptide was designed, which indicted that CPT could be sustainably released from the hybrid peptide in both human serum and cancer cellular environments. Strikingly, compared with free CPT, the water solubility, cellular uptake, and selectivity towards cancer cells of hybrid peptide LYJ-2 have all been significantly enhanced. Moreover, unlike free CPT or TH19P01, LYJ-2 exhibited selective anti-proliferative and anti-migration effects against SORT1-positive MDA-MB-231 cells. Collectively, this study not only established efficient strategies to improve the solubility and anticancer potential of chemotherapeutic agent CPT, but also provided important references for the future development of TH19P01 based PDCs targeting SORT1.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular , Antineoplásicos , Camptotecina , Proliferação de Células , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Camptotecina/farmacologia , Camptotecina/química , Camptotecina/síntese química , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Proliferação de Células/efeitos dos fármacos , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/síntese química , Relação Estrutura-Atividade , Estrutura Molecular , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Movimento Celular/efeitos dos fármacos
5.
Endocr Pract ; 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39241965

RESUMO

OBJECTIVE: This study evaluates the relationship between the Life's Essential 8 (LE8) scoring system and all-cause and cause-specific mortality among obese individuals using National Health and Nutrition Examination Survey data. METHODS: Data from 9143 obese participants (BMI ≥30 kg/m2) collected between 2005 and 2018 were analyzed. Participants were categorized based on their LE8 scores: low cardiovascular health (Low CVH, n = 2264), moderate cardiovascular health (Moderate CVH, n = 6541), and high cardiovascular health (High CVH, n = 338). Associations between LE8 scores and mortality were assessed using Kaplan-Meier survival analysis and Cox proportional hazards models. RESULTS: Over a median follow-up of 7.3 years, there were 867 all-cause deaths (9.5%), including 246 cardiovascular disease (CVD) deaths (2.7%) and 621 non-CVD deaths (6.8%). In multivariable Cox regression analysis, compared to the Low CVH group, the Moderate CVH group had an adjusted hazard ratio (HR) for all-cause mortality of 0.63 (95% CI: 0.55-0.72), and the High CVH group had an HR of 0.25 (95% CI: 0.10-0.60). For CVD mortality, the HRs were 0.61 (95% CI: 0.47-0.78) for Moderate CVH and 0.19 (95% CI: 0.03-1.38) for High CVH. For non-CVD mortality, the HRs were 0.64 (95% CI: 0.54-0.75) for Moderate CVH and 0.27 (95% CI: 0.10-0.72) for High CVH. Each 10-point increase in LE8 score was associated with a 20% reduction in all-cause mortality (P < .001), 21% reduction in CVD mortality (P < .001), and 20% reduction in non-CVD mortality (P < .001). CONCLUSION: Higher LE8 scores are significantly associated with lower rates of all-cause, CVD, and non-CVD mortality among obese individuals. These findings support the LE8 scoring system as an effective predictor of health status and mortality risk.

6.
Chem Biodivers ; : e202401938, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39242361

RESUMO

A dimeric citrinin derivative with a unique spiro[chroman-2,3'-isochroman] skeleton, xerucitrinic acid C (1), and a new citrinin derivative, cladosporin E (6), along with ten known polyketides (2-5 and 7-12), were isolated from the mangrove sediment-derived fungus Talaromyces sp. SCSIO 41428. Their structures were elucidated through comprehensive spectral data analysis. The absolute configurations of 1 and 6 were determined by quantum chemical calculations. Compound 1 exhibited significant inhibitory effects on Staphylococcus aureus and Streptococcus suis, with the MIC of 25 µg/mL for both bacterial strains. Xerucitrinin C (3) exhibited significant radical scavenging activity against DPPH, with an IC50 value of 25.4 µM, and also demonstrated inhibitory activity against phosphodiesterase-4 (PDE4). Moreover, cladosporin C (7) notably inhibited prostate cancer cells PC-3 and 22Rv1, with IC50 values of 6.10 and 9.25 µM, respectively.

7.
Chemistry ; 29(52): e202301469, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37385953

RESUMO

In this work, an organic-inorganic hybrid crystal, violet-crystal (VC), was used to etch the nickel foam (NF) to fabricate a self-standing electrode for the water oxidation reaction. The efficacy of VC-assisted etching manifests the promising electrochemical performance towards the oxygen evolution reaction (OER), requiring only ~356 and ~376 mV overpotentials to reach 50 and 100 mA cm-2 , respectively. The OER activity improvement is attributed to the collectively exhaustive effects arising from the incorporation of various elements in the NF, and the enhancement of active site density. Furthermore, the self-standing electrode is robust, exhibiting a stable OER activity after 4,000 cyclic voltammetry cycles, and ~50 h. The anodic transfer coefficients (αa ) show that the first electron transfer step is the rate-determining step on the surface of NF-VCs-1.0 (NF etched by 1 g of VCs) electrode, while the chemical step involving dissociation following the first electron transfer step is identified as the rate-limiting step in other electrodes. The lowest Tafel slope value observed in the NF-VCs-1.0 electrode indicates the high surface coverage of oxygen intermediates and more favorable OER reaction kinetics, as confirmed by high interfacial chemical capacitance and low charge transport/interfacial resistance. This work demonstrates the importance of VCs-assisted etching of NF to activate the OER, and the ability to predict reaction kinetics and rate-limiting step based on αa values, which will open new avenues to identify advanced electrocatalysts for the water oxidation reaction.

8.
J Nat Prod ; 86(5): 1240-1250, 2023 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-37145877

RESUMO

Mass spectrometry-based dereplication and prioritization led to the discovery of four multi-N-methylated cyclodecapeptides, auyuittuqamides E-H (1-4), from a soil-derived Sesquicillium sp. The planar structures of these compounds were elucidated based on analysis of HRESIMS and NMR data. Absolute configurations of the chiral amino acid residues were assigned by a combination of the advanced Marfey's method, chiral-phase LC-MS analysis, and J-based configuration analysis, revealing that 1-4 contain both d- and l-isomers of N-methylleucine (MeLeu). Differentiation of d- and l-MeLeu in the sequence was achieved by advanced Marfey's analysis of the diagnostic peptide fragments generated from partial hydrolysis of 1. Bioinformatic analysis identified a putative biosynthetic gene cluster (auy) for auyuittuqamides E-H, and a plausible biosynthetic pathway was proposed. These newly identified fungal cyclodecapeptides (1-4) displayed in vitro growth inhibitory activity against vancomycin-resistant Enterococcus faecium with MIC values of 8 µg/mL.


Assuntos
Aminoácidos , Fragmentos de Peptídeos , Aminoácidos/química , Cromatografia Líquida , Espectrometria de Massas , Estrutura Molecular , Peptídeos Cíclicos/análise , Peptídeos Cíclicos/química
9.
Nat Mater ; 20(10): 1378-1384, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34341524

RESUMO

Thermoelectric materials generate electric energy from waste heat, with conversion efficiency governed by the dimensionless figure of merit, ZT. Single-crystal tin selenide (SnSe) was discovered to exhibit a high ZT of roughly 2.2-2.6 at 913 K, but more practical and deployable polycrystal versions of the same compound suffer from much poorer overall ZT, thereby thwarting prospects for cost-effective lead-free thermoelectrics. The poor polycrystal bulk performance is attributed to traces of tin oxides covering the surface of SnSe powders, which increases thermal conductivity, reduces electrical conductivity and thereby reduces ZT. Here, we report that hole-doped SnSe polycrystalline samples with reagents carefully purified and tin oxides removed exhibit an ZT of roughly 3.1 at 783 K. Its lattice thermal conductivity is ultralow at roughly 0.07 W m-1 K-1 at 783 K, lower than the single crystals. The path to ultrahigh thermoelectric performance in polycrystalline samples is the proper removal of the deleterious thermally conductive oxides from the surface of SnSe grains. These results could open an era of high-performance practical thermoelectrics from this high-performance material.

10.
Small ; 17(17): e2007287, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33719180

RESUMO

Several transition-metal oxides and hydroxides based on earth-abundant elements, such as Fe, Ni, and Co, have emerged as a new generation of oxygen evolution reaction (OER) catalysts due to their low cost, favorable activity, and multifunctional behavior. However, the relatively complicated surface structuring methods, high Tafel slope, and low stability hinder their practical applications to replace the conventional Ir- and Ru-based catalysts. Herein, a strategy to construct hierarchically architected mixed oxides on conductive substrates (e.g., ITO and Ni foam) via a nanosheet (NS) deposition and subsequent bidirectional nanomodification approach, with metal salts in an aprotic polar solvent (e.g., acetone) as the primary modifying reactants is reported. This strategy is used to prepare NiO-based NSs with nanopores, nanobranches, or a combination of both, containing up to four transition metal elements. Record-low Tafel slope (22.3 mV·dec-1 , ≈lowest possible by computational predictions) and week-long continuous operation durability are achieved by FeMnNi-O NSs supported on Ni foams. Taken together, properly designed hierarchical mixed oxide electrodes may provide a cost-effective route to generating high, reliable, and stable OER catalytic activities, paving the way for both new electrocatalyst design and practical water-splitting devices.

11.
Mar Drugs ; 19(3)2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809116

RESUMO

With the widespread occurrence of aquaculture diseases and the broad application of antibiotics, drug-resistant pathogens have increasingly affected aquatic animals' health. Marine probiotics, which live under high pressure in a saltwater environment, show high potential as a substitute for antibiotics in the field of aquatic disease control. In this study, twenty strains of non-hemolytic bacteria were isolated from the intestine of wild oysters and perch, and a model of Caenorhabditis elegans infected by Vibrio anguillarum was established. Based on the model, ML1206, which showed a 99% similarity of 16S rRNA sequence to Planococcus maritimus, was selected as a potential marine probiotic, with strong antibacterial capabilities and great acid and bile salt tolerance, to protect Caenorhabditis elegans from being damaged by Vibrio anguillarum. Combined with plate counting and transmission electron microscopy, it was found that strain ML1206 could significantly inhibit Vibrio anguillarum colonization in the intestinal tract of Caenorhabditis elegans. Acute oral toxicity tests in mice showed that ML1206 was safe and non-toxic. The real-time qPCR results showed a higher expression level of genes related to the antibacterial peptide (ilys-3) and detoxification (ugt-22, cyp-35A3, and cyp-14A3) in the group of Caenorhabditis elegans protected by ML1206 compared to the control group. It is speculated that ML1206, as a potential probiotic, may inhibit the infection caused by Vibrio anguillarum through stimulating Caenorhabditis elegans to secrete antibacterial effectors and detoxification proteins. This paper provides a new direction for screening marine probiotics and an experimental basis to support the potential application of ML1206 as a marine probiotic in aquaculture.


Assuntos
Caenorhabditis elegans/microbiologia , Planococáceas , Probióticos/administração & dosagem , Vibrioses/prevenção & controle , Animais , Aquicultura , Feminino , Intestinos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Ostreidae/microbiologia , Planococáceas/genética , Planococáceas/isolamento & purificação , Probióticos/toxicidade , RNA Ribossômico 16S , Sobrevida , Vibrio/isolamento & purificação
12.
Rare Metals ; 40(8): 2017-2025, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33679100

RESUMO

Owing to their high performance and earth abundance, copper sulfides (Cu2-x S) have attracted wide attention as a promising medium-temperature thermoelectric material. Nanostructure and grain-boundary engineering are explored to tune the electrical transport and phonon scattering of Cu2-x S based on the liquid-like copper ion. Here multiscale architecture-engineered Cu2-x S are fabricated by a room-temperature wet chemical synthesis combining mechanical mixing and spark plasma sintering. The observed electrical conductivity in the multiscale architecture-engineered Cu2-x S is four times as much as that of the Cu2-x S sample at 800 K, which is attributed to the potential energy filtering effect at the new grain boundaries. Moreover, the multiscale architecture in the sintered Cu2-x S increases phonon scattering and results in a reduced lattice thermal conductivity of 0.2 W·m-1·K-1 and figure of merit (zT) of 1.0 at 800 K. Such a zT value is one of the record values in copper sulfide produced by chemical synthesis. These results suggest that the introduction of nanostructure and formation of new interface are effective strategies for the enhancement of thermoelectric material properties. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s12598-020-01698-6) contains supplementary material, which is available to authorized users.

13.
Age Ageing ; 49(6): 1062-1070, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-32638996

RESUMO

BACKGROUND: the ageing population has increased in many countries, including China. However, reference intervals (RIs) for older people are rarely established because of difficulties in selecting reference individuals. Here, we aimed to analyse the factors affecting biochemical analytes and establish RI and age-related RI models for biochemical analytes through mining real-world big data. METHODS: data for 97,220 individuals downloaded from electronic health records were included. Three derived databases were established. The first database included 97,220 individuals and was used to build age-related RI models after identifying outliers by the Tukey method. The second database consisted of older people and was used to establish variation source models and RIs for biochemical analytes. Differences between older and younger people were compared using the third database. RESULTS: sex was the main source of variation of biochemical analytes for older people in the variation source models. The distributions of creatinine and uric acid were significantly different in the RIs of biochemical analytes for older people established according to sex. Age-related RI models for biochemical analytes that were most affected by age were built and visualized, revealing various patterns of changes from the younger to older people. CONCLUSION: the study analysed the factors affecting biochemical analytes in older people. Moreover, RI and age-related RI models of biochemical analytes for older people were established to provide important insight into biological processes and to assist clinical use of various biochemical analytes to monitor the status of various diseases for older people.


Assuntos
Mineração de Dados , Idoso , China , Bases de Dados Factuais , Humanos , Valores de Referência
14.
Phys Chem Chem Phys ; 21(17): 8897-8905, 2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-30982834

RESUMO

Observations of the initial lithiation of NiO electrodes demonstrate how to seed conversion reactions using interfaces in a thin film Ni/NiO bilayer architecture. Operando X-ray reflectivity (XRR) reveals that structural changes in a NiO film begin at potentials near the theoretical reduction potential (1.8-2.0 V) with detectable lithiation of both the buried Ni/NiO interface and the outer NiO surface that occur prior to the reaction of the NiO film. This initial conversion reaction is most pronounced in ultrathin NiO films (∼20 Å) with only small changes to the NiO film surface for thicker films (∼67 Å). The limited reactivity of thicker NiO films probed using operando grazing incidence small-angle X-ray scattering (GISAXS) shows the growth of nanoparticles at the electrode/electrolyte interface during initial lithium ion insertion, with a 16-20 Å average radius. Ex situ X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and scanning transmission electron microscopy/electron energy loss spectroscopy (STEM/EELS) confirm our conclusions about the morphological changes accompanying initial stage of lithiation in these conversion reaction electrodes. The present study reveals the interconnected challenges of solid-solid transitions, overpotentials, interfacial nucleation and kinetics, and transition metal dissolution in conversion-type electrodes that are critical for their use as electrodes in lithium-ion batteries.

15.
Plant Dis ; 103(11): 2925-2932, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31449436

RESUMO

With increasing concerns of the environmental problems associated with current fungicide application, investigation of alternative, environmentally compatible biopesticides for plant disease management is needed. A total of 113 strains associated with Acanthus ilicifolius Linn in the Maipo Reserve, Hong Kong, were isolated and identified. In vitro assay with crude extracts of bacterial fermentation cultures identified ∼26% of the isolates producing antimicrobial compounds against a variety of agriculturally important phytopathogens. Selected crude extracts with inhibition to Colletotrichum fructicola and Magnaporthe oryzae growth significantly suppressed anthracnose and rice blast development in pear fruits and rice plants, respectively, when applied at 50 µg ml-1. Furthermore, 10 of 14 selected crude extracts with good antimicrobial activities had no significant differences in toxicity to the genus Chlorella compared with the control when used at 25 µg ml-1, whereas Amistar Top and Mancozeb completely killed the alga under the same concentration. These data illustrate the potential of natural products from mangrove rhizosphere bacteria in future agricultural application.


Assuntos
Bactérias , Agentes de Controle Biológico , Produtos Biológicos , Chlorella , Doenças das Plantas , Rizosfera , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Bactérias/química , Bactérias/efeitos dos fármacos , Agentes de Controle Biológico/química , Agentes de Controle Biológico/isolamento & purificação , Agentes de Controle Biológico/farmacologia , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/farmacologia , Hong Kong , Doenças das Plantas/prevenção & controle
16.
Nano Lett ; 18(11): 7104-7110, 2018 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-30296380

RESUMO

Molybdenum disulfide (MoS2) has been recognized as a promising cost-effective catalyst for water-splitting hydrogen production. However, the desired performance of MoS2 is often limited by insufficient edge-terminated active sites, poor electrical conductivity, and inefficient contact to the supporting substrate. To address these limitations, we developed a unique nanoarchitecture (namely, winged Au@MoS2 heterostructures enabled by our discovery of the "seeding effect" of Au nanoparticles for the chemical vapor deposition synthesis of vertically aligned few-layer MoS2 wings). The winged Au@MoS2 heterostructures provide an abundance of edge-terminated active sites and are found to exhibit dramatically improved electrocatalytic activity for the hydrogen evolution reaction. Theoretical simulations conducted for this unique heterostructure reveal that the hydrogen evolution is dominated by the proton adsorption step, which can be significantly promoted by introducing sufficient edge active sites. Our study introduces a new morphological engineering strategy to make the pristine MoS2 layered structures highly competitive earth-abundant catalysts for efficient hydrogen production.

17.
Chemistry ; 24(58): 15663-15668, 2018 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-30113103

RESUMO

All-in-one architectures in which uniform nanoscale zero-valent iron nanoparticles are wrapped in hollow porous carbon shells are highly desirable for environmental applications such as wastewater treatment and for use as catalysts, but their preparation remains a significant challenge. Herein, a spatially confined strategy for the in situ preparation of uniform Fe0 @mC (mC=micro/mesoporous carbon) yolk-shell nanospheres, in which the iron nanoparticles are encapsulated in thin, porous carbon shells, is reported. The elaborately designed Fe0 @mC yolk-shell nanospheres were obtained by utilizing silica- and phenolic-resin-coated magnetite nanoparticle core-shell structures as templates by means of selective etching and in situ thermal reduction. The highly dispersed iron nanoparticles with superior reduction capability can effectively remove metal pollutants (e.g., AuIII , AgI , and CuII ), the carbon shell acts as protective cover and prevents aggregation of iron nanoparticles, and the void space in the capsules serves as a reactor for reduction and catalytic reactions.

18.
Nanotechnology ; 28(8): 085401, 2017 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-27973348

RESUMO

A high-performance supercapacitor electrode is designed and fabricated with the 3D interconnected continuous nanoporous Co/CoO core-shell hybrid nanostructure grown on nickel foam. The Co/CoO core-shell hybrid nanostructures are obtained via a hydrothermal method, followed by high-temperature annealing in hydrogen atmosphere, and finally placed in air at 50 °C for 1 h. The Co/CoO core-shell nanostructure assembled by a conductive metal-core and a CoO shell, brings low resistance, high specific capacitance of 5.632 F cm-2 and good capability stability (81.5% capacitance retention after 6000 cycles). An asymmetric supercapacitor device built by the Co/CoO (positive electrode) and activated carbon (negative electrode) can deliver a working voltage of 1.7 V and display a high energy density of 0.002 67 Wh cm-2 at a power density of 0.001 62 W cm-2, which is far superior to that of a supercapacitor at a similar power density.

19.
Nano Lett ; 16(12): 7696-7702, 2016 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-27782405

RESUMO

There are emerging opportunities to harness diverse and complex geometric architectures based on nominal two-dimensional atomically layered structures. Herein we report synthesis and properties of a new core-shell heterostructure, termed Au@MoS2, where the Au nanoparticle is snugly and contiguously encapsulated by few shells of MoS2 atomic layers. The heterostructures were synthesized by direct growth of multilayer fullerene-like MoS2 shell on Au nanoparticle cores. The Au@MoS2 heterostructures exhibit interesting light-matter interactions due to the structural curvature of MoS2 shell and the plasmonic effect from the underlying Au nanoparticle core. We observed significantly enhanced Raman scattering and photoluminescence emission on these heterostructures. We attribute these enhancements to the surface plasmon-induced electric field, which simulations show to mainly localize within the MoS2 shell. We also found potential evidence for the charge transfer-induced doping effect on the MoS2 shell. The DFT calculations further reveal that the structural curvature of MoS2 shell results in a modification of its electronic structure, which may facilitate the charge transfer from MoS2 to Au. Such Au@MoS2 core-shell heterostructures have the potential for future optoelectronic devices, optical imaging, and other energy-environmental applications.

20.
J Intell ; 12(8)2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39195122

RESUMO

This study investigates the impact of math-gender stereotypes on students' academic performance using data from the China Education Panel Survey (CEPS), which surveyed nationally representative middle schools in China. Our sample comprises over 2000 seventh-grade students, with an average age of 13 and a standard deviation of 0.711. Among these students, 52.4% are male, and 47.6% are female. Employing a fixed effects model and instrumental variable, our findings are as follows. First, over half of the male students believe that boys are better at math than girls, and they also perceive that their parents and society hold the same belief. In contrast, fewer than half of the female students hold this belief or perception. Intriguingly, among these students, female math performance surpasses that of males. Second, stereotypes hinder female math performance, especially among low-achieving ones, while benefiting high-achieving male students. Finally, perceptions of societal stereotypes have the greatest effect on math performance, followed by self-stereotypes and perceptions of parental stereotypes. Understanding the implications of these findings highlights the importance of addressing math-gender stereotypes to promote equal participation and success for both genders in STEM fields.

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