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1.
J Ethnopharmacol ; 325: 117889, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38336183

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: The fruit of Lycium barbarum L. (goji berry) is a traditional Chinese medicine and is often used to improve vision. While various goji cultivars may differentially treat retinal degeneration, however their comparative effectiveness remains unclear. AIM OF THE STUDY: To evaluate the protective effects of four goji cultivars on NaIO3-induced retinal degeneration mouse model and identify the most therapeutically potent cultivar. MATERIALS AND METHODS: The principal compounds in the extracts of four goji cultivars were characterized by UPLC-Q-TOF/MS. A retinal degeneration mouse model was established via NaIO3 injection. Dark-light transition and TUNEL assays were used to assess visual function and retinal apoptosis. The levels of antioxidative, inflammatory, and angiogenic markers in serums and eyeballs were measured. Hierarchical cluster analysis, principal component analysis and partial least squares-discriminant analysis were used to objectively compare the treatment responses. RESULTS: Sixteen compounds were identified in goji berry extracts. All goji berry extracts could reverse NaIO3-induced visual impairment, retinal damage and apoptosis. The samples from the cultivar of Ningqi No.1 significantly modulated oxidative stress, inflammation, and vascular endothelial growth factor levels, which are more effectively than the other cultivars based on integrated multivariate profiling. CONCLUSION: Ningqi No.1 demonstrated a stronger protective effect on mouse retina than other goji cultivars, and is a potential variety for further research on the treatment of retinal degeneration.


Assuntos
Lycium , Degeneração Retiniana , Camundongos , Animais , Degeneração Retiniana/induzido quimicamente , Degeneração Retiniana/tratamento farmacológico , Lycium/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Antioxidantes/metabolismo , Estresse Oxidativo , Modelos Animais de Doenças
2.
Nat Commun ; 15(1): 1157, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38326296

RESUMO

Blue phosphorene (BlueP), a theoretically proposed phosphorous allotrope with buckled honeycomb lattice, has attracted considerable interest due to its intriguing properties. Introducing chirality into BlueP can further enrich its physical and chemical properties, expanding its potential for applications. However, the synthesis of chiral BlueP remains elusive. Here, we demonstrate the growth of large-area BlueP films on Cu(111), with lateral size limited by the wafer dimensions. Importantly, we discovered that the BlueP is characterized by an ultraflat honeycomb lattice, rather than the prevailing buckled structure, and develops highly ordered spatial chirality plausibly resulting from the rotational stacking with the substrate and interface strain release, as further confirmed by the geometric phase analysis. Moreover, spectroscopic measurements reveal its intrinsic metallic nature and different characteristic quantum oscillations in the image-potential states, which can be exploited for a range of potential applications including polarization optics, spintronics, and chiral catalysis.

3.
Clin Biomech (Bristol, Avon) ; 106: 106008, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37257273

RESUMO

BACKGROUND: Hindfoot valgus is one of the most prevalent foot deformities in cerebral palsy children. Investigating the muscle activation patterns of cerebral palsy children with hindfoot valgus is crucial to understand their abnormal gait different from typically developing children. METHODS: Electromyography data of 20 cerebral palsy children with hindfoot valgus and 20 typically developing children were recorded for tibialis anterior, peroneal longus, and gastrocnemius medialis. The activation onset and offset times, normalized peak electromyography amplitude, average electromyography amplitude and integral electromyography amplitude for 20 completed cycles were averaged for data analysis. The co-activation index and activation percentage of peroneal longus were used to evaluate the co-activation level for tibialis anterior and peroneal longus muscles. FINDINGS: Compared with typically developing children, the activation onset of tibialis anterior and the activation offset of tibialis anterior, peroneal longus, and gastrocnemius medialis were significantly delayed in cerebral palsy children; moreover, the muscle activation durations of tibialis anterior, peroneal longus, and gastrocnemius medialis were significantly longer, and the normalized average electromyography amplitude of tibialis anterior, peroneal longus and gastrocnemius medialis, and the normalized integral electromyography amplitude of tibialis anterior were significantly lower in cerebral palsy children. Furthermore, for cerebral palsy children, the co-activation index was greater, and the peroneal longus muscles activation percentage was lower in the stance phase and greater in the swing phase than that of typically developing children. INTERPRETATION: The lower leg muscle activation patterns in cerebral palsy children were found to be abnormal.


Assuntos
Paralisia Cerebral , Perna (Membro) , Criança , Humanos , Paralisia Cerebral/complicações , Eletromiografia , Músculo Esquelético/fisiologia , Caminhada/fisiologia , Marcha/fisiologia , Espasticidade Muscular
4.
J Am Chem Soc ; 145(3): 1660-1667, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36633835

RESUMO

Conformational arrangements in polymers on surfaces determine the overall shape as well as the potential properties. It is generally believed that conformational diversity leads to uncontrollable or disordered structures in on-surface synthesis. However, in this study, we obtain two well-ordered self-assembled covalently linked wavy chains with site-selective conformational switching via the Ullmann reaction of 1,2-bis(3-bromophenyl)ethane with multiple conformations on Ag(111). Two kinds of wavy chains exhibit distinct conformational arrangements, where chain I contains one repeating unit conformation of -cis-trans1-cis-trans1-cis-cis-trans1-, while the adjacent parallel parts in wavy chain II have two different conformational arrangements of -cis-cis-trans1- and -cis-cis-trans2-. Wavy chains coassemble with dissociated bromine atoms, suggesting that the Br···H-C interactions between Br atoms and molecular chains are crucial for the construction of ordered wavy chains. High-resolution scanning tunneling microscopy is employed to reveal the surface reaction process at the molecular scale. In depth growth mechanism analysis combined with density functional theory calculations unveils that the substrate also plays an important role in the fabrication of well-ordered wavy chains. The present work extends the surface reaction of conformational flexible precursors.

5.
Phys Rev Lett ; 129(2): 026802, 2022 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-35867437

RESUMO

Magnetic molecules on surfaces have been widely investigated to reveal delicate interfacial couplings and for potential technological applications. In these endeavors, one prevailing challenge is how to preserve or recover the molecular spins, especially on highly metallic substrates that can readily quench the magnetic moments of the admolecules. Here, we use scanning tunneling microscopy and spectroscopy to exploit the semimetallic nature of antimony and observe, surprisingly yet pleasantly, that the spin of Co-phthalocyanine is well preserved on Sb(111), as unambiguously evidenced by the emergent strong Kondo resonance across the molecule. Our first-principles calculations further confirm that the optimal density of states near the Fermi level of the semimetal is a decisive factor, weakening the overall interfacial coupling, while still ensuring sufficiently effective electron-spin scattering in the many-body system. Beyond isolated admolecules, we discover that each of the magnetic moments in a molecular dimer or a densely packed island is distinctly preserved as well, rendering such molecular magnets immense potentials for ultrahigh density memory devices.

6.
Small ; 17(43): e2101605, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34310054

RESUMO

Perovskite oxides are studied as electrocatalysts for oxygen evolution reactions (OER) because of their low cost, tunable structure, high stability, and good catalytic activity. However, there are two main challenges for most perovskite oxides to be efficient in OER, namely less active sites and low electrical conductivity, leading to limited catalytic performance. To overcome these intrinsic obstacles, various strategies are developed to enhance their catalytic activities in OER. In this review, the recent developments of these strategies is comprehensively summarized and systematically discussed, including composition engineering, crystal facet control, morphology modulation, defect engineering, and hybridization. Finally, perspectives on the design of perovskite oxide-based electrocatalysts for practical applications in OER are given.

7.
Nano Lett ; 19(9): 6144-6151, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31438678

RESUMO

The heterostructures of the ferromagnet (Cr2Te3) and topological insulator (Bi2Te3) have been grown by molecular beam epitaxy. The topological Hall effect as evidence of the existence of magnetic skyrmions has been observed in the samples in which Cr2Te3 was grown on top of Bi2Te3. Detailed structural characterizations have unambiguously revealed the presence of intercalated Bi bilayer nanosheets right at the interface of those samples. The atomistic spin-dynamics simulations have further confirmed the existence of magnetic skyrmions in such systems. The heterostructures of ferromagnet and topological insulator that host magnetic skyrmions may provide an important building block for next generation of spintronics devices.

8.
ACS Appl Mater Interfaces ; 11(30): 26994-27003, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31290644

RESUMO

Despite layered LiNixCoyMnzO2 having drawn much attention for their high capacity and high energy density, they still endure strong capacity decay upon prolonged cycling and high C-rates, primarily due to sluggish Li+ and charge-transfer kinetics and detrimental parasitic reactions with the electrolyte. To address these issues, application of a surface-coating layer made of V2O5/LiV3O8 on LiNi0.4Co0.2Mn0.4O2 (V-NCM) is pursued. Benefiting from the ionic conductivity of LiV3O8 and the electronic conductivity of V2O5, resulting in both enhanced Li+ diffusion and charge-transfer kinetics, the coated material offers significantly improved C-rate capability. Additionally, better long-term cycling performance is achieved mostly due to the mitigated parasitic reactions at the electrode/electrolyte interface that result in lower structural degradation. As a result, Li/V-NCM cells deliver over 100 mA h g-1 capacity at 10 C and also achieve 86.1% (2 C) and 94.1% (10 C) capacity retention after 200 cycles. These V-NCM cells operate quite stably even at elevated temperature, that is, 40 and 60 °C. The coating strategy herein reported may also be useful to enhance the cycling stability and C-rate capability of other layered cathode materials.

9.
ChemSusChem ; 12(14): 3355-3362, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31074099

RESUMO

The development of earth-abundant, economical, and efficient photocatalysts to boost water splitting is a key challenge for the practical large-scale application of hydrogen energy. In this study, g-C3 N4 loaded with different tungsten compounds (W2 C, WS2 , and W2 N) is found to exhibit enhanced photocatalytic activities. W2 C/g-C3 N4 displays the highest activity for the photocatalytic reaction with a H2 evolution rate of up to 98 µmol h-1 , as well as remarkable recycling stability. The excellent photocatalytic activity of W2 C/g-C4 N3 is attributed to the suitable band alignment in W2 C/g-C4 N3 and high HER activity of the W2 C cocatalyst, which promotes the separation and transfer of carriers and hydrogen evolution at the surface. These findings demonstrate that the tungsten carbide cocatalyst is more active for the photocatalytic reaction than the sulfide or nitride, paving a way for the design of novel and efficient carbides as cocatalysts for photocatalysis.

10.
Zhongguo Zhong Yao Za Zhi ; 43(13): 2664-2669, 2018 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-30111014

RESUMO

In order to investigate the genetic difference on medicinal components of Scutellaria baicalensis from different provenances on the genetic difference, the S. baicalensis provenance tests were arranged by randomized block design.Excavating the crude drugs that have been growing for three years, with the same drying process, the content of baicalin, baicalein, wogonoside, wogonin and laminarin A in S. baicalensis were detected by HPLC, and then the data were analyzed. The results indicated that the content of baicalin in different provenances of S. baicalensis was significantly different (P<0.05), while the variation of baicalein reached extremely significant level (P<0.01). Cluster analysis showed that if the distance was divided by 5.0, the provenances in Chengde, Hebei province were divided into two independent populations, while the other two populations had large geographic spans. The results show that the significant geographical variations exist in the content of medicinal components in S. baicalensis. The study laid a theoretical foundation of provenance selection of S. baicalensis.


Assuntos
Scutellaria baicalensis , Cromatografia Líquida de Alta Pressão , Flavanonas , Flavonoides , Geografia , Raízes de Plantas
11.
ChemSusChem ; 9(19): 2824-2831, 2016 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-27572550

RESUMO

BiVO4 has been identified as one of the excellent visible light responsive photoanodes for use in photoelectrochemical (PEC) water splitting. However, pristine BiVO4 usually exhibits relative low photocatalytic properties owing to insufficient charge separation and transport characteristics. Although the marginal n-type doping of higher valence ions can obviously raise the photocurrent value, it by no means improves the PEC stability. In this work, we successfully enhanced the PEC stability of BiVO4 by doping Fe ions in substitution of Bi. Density functional theory calculations have illustrated that Fe-doping would result in an impurity band in the forbidden gap, and thus narrow its energy gap. More importantly, Fe-doping can synergize with other means to further improve the PEC activities of BiVO4 . Therefore, we fabricated a nanoporous Fe/W co-doped BiVO4 photoelectrode, and then loaded the metal-organic framework (MOF) MIL-100(Fe) as cocatalyst to further promote the separation of charge carriers. To the best of our knowledge, MOFs have not yet been utilized as a cocatalyst to facilitate the charge separation, which could increase the photocurrent density of Fe/W co-doped BiVO4 .


Assuntos
Bismuto/química , Eletrodos , Ferro/química , Tungstênio/química , Vanadatos/química , Catálise , Técnicas Eletroquímicas , Microscopia Eletrônica de Varredura , Processos Fotoquímicos , Espectrofotometria Ultravioleta
12.
Zhongguo Zhong Yao Za Zhi ; 41(11): 2049-2054, 2016 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-28901100

RESUMO

By measuring the growth data of Scutellaria baicalensis in different cutting-seedling and determined active ingredient contents by HPLC and ultraviolet spectrophotometric determination. such as flavonoids. baicalin. wogonoside. baicalein. wogonin. oroxylin A. scutellarin. luteolin. and apigenin in the whole plant. Under circumstances of guaranteeing the quality and yield of medicinal materials. the yield of medicinal materials. and stems and leaves reached 193.60,63.21 kg/mu after twice cutting seedling. Not only yield but also active ingredient contents have been improved to some extent. the contents of flavonoids. baicalin. wogonoside. baicalein. wogonin. oroxylin A reached 18.52%. 15.13%. 4.03%. 1.04%. 1.04%. 0.12%. respectively in roots. Luteolin was not detected in young stems and leaves of S. baicalensis,the contents of other active ingredients such as scutellarin. luteolin and apigenin reached 7.00%. 0.96%. 0.04% respectively under twice cutting seedling. Therefore. regular cutting seedling could be regard as a new cultivation technique for wider range of promotion. And gaining high quality and yield of medicinal materials and tea with the purpose of rational utilization of natural resources and promoting the development of integration of herbal combination.


Assuntos
Flavanonas/análise , Flavonoides/análise , Scutellaria baicalensis/química , Plântula/crescimento & desenvolvimento , Agricultura/métodos , Cromatografia Líquida de Alta Pressão , Raízes de Plantas/química , Plantas Medicinais/química , Plantas Medicinais/crescimento & desenvolvimento , Scutellaria baicalensis/crescimento & desenvolvimento , Espectrofotometria Ultravioleta
13.
Nanoscale Res Lett ; 10(1): 1043, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26293493

RESUMO

We report the first-principle study on the recovery and linearization of Dirac cones in the electronic band structures of a few bilayer Sb(111) films (n-BL Sb) by surface modification. Due to the interaction between the surface states on the two surfaces of a free-standing film, the distorted Dirac cone in n-BL Sb(111) (n < 5) disappears. We demonstrate that the Dirac cone can be restored by functionalizing one surface with certain atoms including H, Ag, and Au, to reduce the inter-surface interaction. We further show that an ideal Dirac cone with linear dispersion of topological surface states near the zone center can be realized by functionalizing both surfaces of the film with oxygen, which enhances spin-orbital coupling. The realization of Dirac cone by surface functionalization shows promise for applications of topologic materials to spintronic devices and their operation in complicated conditions.

14.
Nano Lett ; 15(1): 80-7, 2015 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-25495154

RESUMO

Topological insulators (TIs) are a new type of electronic materials in which the nontrivial insulating bulk band topology governs conducting boundary states with embedded spin-momentum locking. Such edge states are more robust in a two-dimensional (2D) TI against scattering by nonmagnetic impurities than in its three-dimensional (3D) variant, because in 2D the two helical edge states are protected from the only possible backscattering. This makes the 2D TI family a better candidate for coherent spin transport and related applications. While several 3D TIs are already synthesized experimentally, physical realization of 2D TI is so far limited to hybrid quantum wells with a tiny bandgap that does not survive temperatures above 10 K. Here, combining first-principles calculations and scanning tunneling microscopy/spectroscopy (STM/STS) experimental studies, we report nontrivial 2D TI phases in 2-monolayer (2-ML) and 4-ML Bi(110) films with large and tunable bandgaps determined by atomic buckling of Bi(110) films. The gapless edge states are experimentally detected within the insulating bulk gap at 77 K. The band topology of ultrathin Bi(110) films is sensitive to atomic buckling. Such buckling is sensitive to charge doping and could be controlled by choosing different substrates on which Bi(110) films are grown.

15.
Sci Rep ; 3: 2010, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23774610

RESUMO

Based on an inverted bulk band order, antimony thin films presumably could become topological insulators if quantum confinement effect opens up a gap in the bulk bands. Coupling between topological surface states (TSS) from opposite surfaces, however, tends to degrade or even destroy their novel characters. Here the evolution and coupling of TSS on Sb(111) thin films from 30 bilayers down to 4 bilayers was investigated using in-situ Fourier-transform scanning tunneling spectroscopy and density functional theory computations. On a 30-bilayer sample, quasi-particle interference patterns are generated by the scattering of TSS from the top surface only. As the thickness decreases, inter-surface coupling degrades spin polarisation of TSS and opens up new wavevector-dependent scattering channels, resulting in spin degenerate states in most part of the surface Brillouin zone, whereas the TSS near the zone centre exhibit little inter-surface coupling, so they remain spin-polarised without opening a gap at the Dirac point.

16.
Nanotechnology ; 23(37): 375603, 2012 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-22922593

RESUMO

Ultra-fine Au nanoparticles (NPs) show great application potential in catalysis. Size-tunable Au NPs have been fabricated on MoS(2) covered with monolayer 3,4,5,10-perylene tetracarboxylic dianhydride (PTCDA), and the morphological evolution as a function of Au deposition amount was investigated using scanning tunneling microscopy (STM). The PTCDA molecules act as a surfactant to stabilize ultra-fine Au NPs. Molecular scale STM images show that on MoS(2) the Au NPs with PTCDA molecules on top can be formed with height and lateral size down to 1.3 nm and 3.5 nm, respectively. By controlling the deposition amount and annealing temperature, the size of Au NPs can be tuned. After annealing at 270 °C to remove PTCDA, Au NPs with a linear size ≤5 nm can be obtained on MoS(2)(0001), facilitating the characterization of their intrinsic physical and chemical properties using various analytical techniques. In addition, photoemission spectroscopy data reveal charge transfer from Au NPs to PTCDA, indicating that the NPs possess more reactive chemical properties than bulk Au.

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