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1.
Nature ; 634(8032): 80-84, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39322668

RESUMEN

Monoatomic-layered carbon materials, such as graphene1 and amorphous monolayer carbon2,3, have stimulated intense fundamental and applied research owing to their unprecedented physical properties and a wide range of promising applications4,5. So far, such materials have mainly been produced by chemical vapour deposition, which typically requires stringent reaction conditions compared to solution-phase synthesis. Herein, we demonstrate the solution preparation of free-standing nitrogen-doped amorphous monolayer carbon with mixed five-, six- and seven-membered (5-6-7-membered) rings through the polymerization of pyrrole within the confined interlayer cavity of a removable layered-double-hydroxide template. Structural characterizations and first-principles calculations suggest that the nitrogen-doped amorphous monolayer carbon was formed by radical polymerization of pyrrole at the α, ß and N sites subjected to confinement of the reaction space, which enables bond rearrangements through the Stone-Wales transformation. The spatial confinement inhibits the C-C bond rotation and chain entanglement during polymerization, resulting in an atom-thick continuous amorphous layer with an in-plane π-conjugation electronic structure. The spatially confined radical polymerization using solid templates and ion exchange strategy demonstrates potential as a universal synthesis approach for obtaining two-dimensional covalent networks, as exemplified by the successful synthesis of monolayers of polythiophene and polycarbazole.

2.
Proc Natl Acad Sci U S A ; 120(2): e2212250120, 2023 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-36598953

RESUMEN

The interaction of water with TiO2 surfaces is of crucial importance in various scientific fields and applications, from photocatalysis for hydrogen production and the photooxidation of organic pollutants to self-cleaning surfaces and bio-medical devices. In particular, the equilibrium fraction of water dissociation at the TiO2-water interface has a critical role in the surface chemistry of TiO2, but is difficult to determine both experimentally and computationally. Among TiO2 surfaces, rutile TiO2(110) is of special interest as the most abundant surface of TiO2's stable rutile phase. While surface-science studies have provided detailed information on the interaction of rutile TiO2(110) with gas-phase water, much less is known about the TiO2(110)-water interface, which is more relevant to many applications. In this work, we characterize the structure of the aqueous TiO2(110) interface using nanosecond timescale molecular dynamics simulations with ab initio-based deep neural network potentials that accurately describe water/TiO2(110) interactions over a wide range of water coverages. Simulations on TiO2(110) slab models of increasing thickness provide insight into the dynamic equilibrium between molecular and dissociated adsorbed water at the interface and allow us to obtain a reliable estimate of the equilibrium fraction of water dissociation. We find a dissociation fraction of 22 ± 6% with an associated average hydroxyl lifetime of 7.6 ± 1.8 ns. These quantities are both much larger than corresponding estimates for the aqueous anatase TiO2(101) interface, consistent with the higher water photooxidation activity that is observed for rutile relative to anatase.


Asunto(s)
Simulación de Dinámica Molecular , Agua , Agua/química , Titanio/química
3.
Proc Natl Acad Sci U S A ; 120(39): e2306841120, 2023 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-37722061

RESUMEN

Although direct generation of high-value complex molecules and feedstock by coupling of ubiquitous small molecules such as CO2 and N2 holds great appeal as a potential alternative to current fossil-fuel technologies, suitable scalable and efficient catalysts to this end are not currently available as yet to be designed and developed. To this end, here we prepare and characterize SbxBi1-xOy clusters for direct urea synthesis from CO2 and N2 via C-N coupling. The introduction of Sb in the amorphous BiOx clusters changes the adsorption geometry of CO2 on the catalyst from O-connected to C-connected, creating the possibility for the formation of complex products such as urea. The modulated Bi(II) sites can effectively inject electrons into N2, promoting C-N coupling by advantageous modification of the symmetry for the frontier orbitals of CO2 and N2 involved in the rate-determining catalytic step. Compared with BiOx, SbxBi1-xOy clusters result in a lower reaction potential of only -0.3 V vs. RHE, an increased production yield of 307.97 µg h-1 mg-1cat, and a higher Faraday efficiency (10.9%), pointing to the present system as one of the best catalysts for urea synthesis in aqueous systems among those reported so far. Beyond the urea synthesis, the present results introduce and demonstrate unique strategies to modulate the electronic states of main group p-metals toward their use as effective catalysts for multistep electroreduction reactions requiring C-N coupling.

4.
Chem Rev ; 123(13): 8859-8941, 2023 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-37358266

RESUMEN

Amorphous materials are metastable solids with only short-range order at the atomic scale, which results from local intermolecular chemical bonding. The lack of long-range order typical of crystals endows amorphous nanomaterials with unconventional and intriguing structural features, such as isotropic atomic environments, abundant surface dangling bonds, highly unsaturated coordination, etc. Because of these features and the ensuing modulation in electronic properties, amorphous nanomaterials display potential for practical applications in different areas. Motivated by these elements, here we provide an overview of the unique structural features, the general synthetic methods, and the potential for applications covered by contemporary research in amorphous nanomaterials. Furthermore, we discussed the possible theoretical mechanism for amorphous nanomaterials, examining how the unique structural properties and electronic configurations contribute to their exceptional performance. In particular, the structural benefits of amorphous nanomaterials as well as their enhanced electrocatalytic, optical, and mechanical properties, thereby clarifying the structure-function relationships, are highlighted. Finally, a perspective on the preparation and utilization of amorphous nanomaterials to establish mature systems with a superior hierarchy for various applications is introduced, and an outlook for future challenges and opportunities at the frontiers of this rapidly advancing field is proposed.

6.
J Am Chem Soc ; 146(28): 19295-19302, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-38943666

RESUMEN

Oxygen vacancies are generally considered to play a crucial role in the oxygen evolution reaction (OER). However, the generation of active sites created by oxygen vacancies is inevitably restricted by their condensation and elimination reactions. To overcome this limitation, here, we demonstrate a novel photoelectric reconstruction strategy to incorporate atomically dispersed Cu into ultrathin (about 2-3 molecular) amorphous oxyhydroxide (a-CuM, M = Co, Ni, Fe, or Zn), facilitating deprotonation of the reconstructed oxyhydroxide to generate high-valence Cu. The in situ XAFS results and first-principles calculations reveal that Cu atoms are stabilized at high valence during the OER process due to Jahn-Teller distortion, resulting in para-type double oxygen vacancies as dynamically stable catalytic sites. The optimal a-CuCo catalyst exhibits a record-high mass activity of 3404.7 A g-1 at an overpotential of 300 mV, superior to the benchmarking hydroxide and oxide catalysts. The developed photoelectric reconstruction strategy opens up a new pathway to construct in situ stable oxygen vacancies by high-valence Cu single sites, which extends the design rules for creating dynamically stable active sites.

7.
J Am Chem Soc ; 146(19): 13527-13535, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38691638

RESUMEN

Closing the carbon and nitrogen cycles by electrochemical methods using renewable energy to convert abundant or harmful feedstocks into high-value C- or N-containing chemicals has the potential to transform the global energy landscape. However, efficient conversion avenues have to date been mostly realized for the independent reduction of CO2 or NO3-. The synthesis of more complex C-N compounds still suffers from low conversion efficiency due to the inability to find effective catalysts. To this end, here we present amorphous bismuth-tin oxide nanosheets, which effectively reduce the energy barrier of the catalytic reaction, facilitating efficient and highly selective urea production. With enhanced CO2 adsorption and activation on the catalyst, a C-N coupling pathway based on *CO2 rather than traditional *CO is realized. The optimized orbital symmetry of the C- (*CO2) and N-containing (*NO2) intermediates promotes a significant increase in the Faraday efficiency of urea production to an outstanding value of 78.36% at -0.4 V vs RHE. In parallel, the nitrogen and carbon selectivity for urea formation is also enhanced to 90.41% and 95.39%, respectively. The present results and insights provide a valuable reference for the further development of new catalysts for efficient synthesis of high-value C-N compounds from CO2.

8.
Eur Spine J ; 33(2): 695-705, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37874394

RESUMEN

PURPOSE: Although the Roussouly classification has been widely used in surgical planning for adult scoliosis patients, little is known about whether it can be used to guide sagittal correction for adolescent idiopathic scoliosis (AIS) patients. The purpose of this study was to explore whether the Roussouly classification could be used to help surgeons restore the ideal sagittal alignment for AIS patients to avoid the development of proximal junctional kyphosis (PJK). METHODS: In this retrospective cohort study, eighty-seven patients with Lenke 5 AIS who underwent surgery from January 2010 to August 2020 were enrolled and divided into two groups: the PJK group and the non-PJK group. All patients were classified into "current types" and "ideal types" according to two versions of the Roussouly classification, and the mismatch rate was evaluated in terms of the consistency between their current type and ideal type. Student's t test, Mann‒Whitney U test, Pearson's Chi-square test, and others were used to compare the two groups regarding patient demographic characteristics (age, sex, Risser sign, etc.) and radiographic parameters (sagittal vertical axis [SVA]; thoracic kyphosis [TK]; thoracolumbar junctional kyphosis [TLK]; lumbar lordosis [LL]; pelvic incidence [PI]; pelvic tilt [PT]; sacral slope [SS]; upper instrumented vertebra [UIV]; lower instrumented vertebra [LIV]; etc.). Multivariate logistic regression with backwards stepwise selection was performed to identify the risk factors for PJK. RESULTS: PJK was observed in 16 out of 87 patients (18.4%) until the final follow-up. The incidence of PJK was significantly higher in the patients not matching their ideal type than in those who did after surgery (60.9% vs. 3.1%, p = 0.000). The patients with ideal Type 1 had the highest incidence of PJK, while the lowest incidence was observed in patients with ideal Type 2 (50.0% vs. 5.1%, p = 0.000). The PJK group had greater TK, LL, and PI-LL than the non-PJK group before and after surgery. The postoperative PJA in the PJK group was also larger than that in the non-PJK group. Multivariate logistic regression revealed that postoperative Roussouly type mismatch was significantly associated with the occurrence of PJK (OR = 64.2, CI = 9.6-407.1, p = 0.000). CONCLUSIONS: The Roussouly classification could serve as a prognostic tool for PJK in Lenke 5 AIS patients. Corrective surgery should restore sagittal alignment with respect to the patient's ideal sagittal profile (according to the Roussouly classification based on the PI) to decrease the incidence of PJK in AIS patients.


Asunto(s)
Cifosis , Anomalías Musculoesqueléticas , Escoliosis , Adulto , Animales , Humanos , Adolescente , Escoliosis/diagnóstico por imagen , Escoliosis/cirugía , Estudios Retrospectivos , Cifosis/diagnóstico por imagen , Cifosis/cirugía , Ácido Dioctil Sulfosuccínico , Sacro
9.
J Am Chem Soc ; 145(9): 5393-5399, 2023 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-36802574

RESUMEN

As one of the most promising materials for next-generation solar cells, organometallic perovskites have attracted substantial fundamental and applied interest. Using first-principles quantum dynamics calculations, we show that octahedral tilting plays an important role in stabilizing perovskite structures and extending carrier lifetimes. Doping the material with (K, Rb, Cs) ions at the A-site enhances octahedral tilting and the stability of the system relative to unfavorable phases. The stability of doped perovskites is maximized for uniform distribution of the dopants. Conversely, aggregation of dopants in the system inhibits octahedral tilting and the associated stabilization. The simulations also indicate that with enhanced octahedral tilting, the fundamental band gap increases, the coherence time and nonadiabatic coupling decrease, and the carrier lifetimes are thus extended. Our theoretical work uncovers and quantifies the heteroatom-doping stabilization mechanisms, opening up new avenues to enhancing the optical performance of organometallic perovskites.

10.
J Am Chem Soc ; 145(46): 25143-25149, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37941374

RESUMEN

According to the traditional nucleation theory, crystals in solution nucleate under thermal fluctuations with random crystal orientation. Thus, nanosheet arrays grown on a substrate always exhibit disordered arrangements, which impede mass transfer during catalysis. To overcome this limitation, here, we demonstrate stress-induced, oriented nucleation and growth of nanosheet arrays. A regularly self-growing parallel nanosheet array is realized on a curved growth substrate. During electrochemical oxygen production, the ordered array maintains a steady flow of liquids in the microchannels, suppressing the detrimental production of flow-blocking oxygen bubbles typical of randomly oriented nanosheet arrays. Controllable parallel arrays, fully covered fluffy-like ultrathin nanosheets, and amorphous disordered structures altogether enable full-scale design of hierarchical interfaces from the micro- to the atomic scale, significantly improving the otherwise sluggish kinetics of oxygen evolution toward industrial ultrafast production. Record-high ultrafast oxygen production of 135 L·min-1·m-2 with high working current of 4000 mA·cm-2 is steadily achieved at a competitively low cell voltage of 2.862 V. These results and related insights lay the basis for further developments in oriented nucleation and growth of crystals beyond classical nucleation approaches, with benefits for large-scale, industrial electrochemical processes as shown here for ultrafast oxygen production.

11.
J Am Chem Soc ; 145(1): 717-724, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36548984

RESUMEN

Compared with layered materials such as graphite and transitional metal dichalcogenides with highly anisotropic in-plane covalent bonds, freestanding metallic two-dimensional (2D) films with atomic thickness are intrinsically more difficult to achieve. The omnidirectional nature of typical metallic bonds prevents the formation of highly anisotropic atomically thin metallic layers. Herein, we report a ligand regulation strategy to stabilize monoatomic platinum layers by forming a unique lamellar superlattice structure with self-assembled organic ligand layers. We show that the interlayer spacings and coordination environments could be systematically tuned by varying programmable molecular ligands with the designed length and structural motifs, which further modulate the electronic states and catalytic performances. The strategy can be extended for preparing lamellar superlattices with monoatomic metallic layers from silver and gold. Such general and delicate synthetic control provides an exciting model system for systematic investigation of the intriguing structure-property correlation of monoatomic layers and promises a molecular design pathway for heterogeneous catalysts.

12.
J Am Chem Soc ; 145(3): 1759-1768, 2023 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-36607337

RESUMEN

Integrating different reaction sites offers new prospects to address the difficulties in single-atom catalysis, but the precise regulation of active sites at the atomic level remains challenging. Here, we demonstrate a sodium-directed photon-induced assembly (SPA) strategy for boosting the atomic utilization efficiency of single-atom catalysts (SACs) by constructing multifarious Au sites on TiO2 substrate. Na+ was employed as the crucial cement to direct Au single atoms onto TiO2, while the light-induced electron transfer from excited TiO2 to Au(Na+) ensembles contributed to the self-assembly formation of Au nanoclusters. The synergism between plasmonic near-field and Schottky junction enabled the cascade electron transfer for charge separation, which was further enhanced by oxygen vacancies in TiO2. Our dual-site photocatalysts exhibited a nearly 2 orders of magnitude improvement in the hydrogen evolution activity under simulated solar light, with a striking turnover frequency (TOF) value of 1533 h-1 that exceeded other Au/TiO2-based photocatalysts reported. Our SPA strategy can be easily extended to prepare a wide range of metal-coupled nanostructures with enhanced performance for diverse catalytic reactions. Thus, this study provides a well-defined platform to extend the boundaries of SACs for multisite catalysis through harnessing metal-support interactions.

13.
Small ; 19(36): e2207759, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37150859

RESUMEN

Homogeneous and nanometric metal clusters with unique electronic structures are promising for catalysis, however, common synthesis techniques for metal clusters suffer from large size and even metal nanocrystals attributing to their high surface energy and unsaturated configurations. Herein, a generalized rapid annealing strategy for synthesizing a series of supported metal clusters as superior catalysts is developed. Remarkably, TiO2 supported platinum nanoclusters (Pt NC/TiO2 ) exhibits the excellent catalytic activity to realize phenol hydrogenation under mild conditions. The complete phenol conversion rate and 100% selectivity toward KA oil are achieved in aqueous solution at room temperature and normal pressure. Semi-continuous scale up production of KA oil is successfully performed under mild conditions. Such excellent performance mainly originates from the partial reconstruction of Pt NC/TiO2 in aqueous phenol solution. Considering that the phenol can be produced from lignin, this study underpins a facile, sustainable, and economical route to synthesize nylon from biomass.

14.
J Med Virol ; 95(10): e29170, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37822054

RESUMEN

Immunogenicity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) bivalent mRNA-1273.214 vaccine (Original/Omicron B.1.1.529 [BA.1]) is underreported in vulnerable older adults in congregate care settings. In residents of 26 long-term care and retirement homes in Ontario, Canada, humoral (i.e., serum anti-spike and anti-receptor binding domain [anti-RBD]) IgG and IgA antibodies and live SARS-CoV-2 neutralization) and cellular (i.e., CD4+ and CD8+ activation-induced marker spike-specific T cell memory) responses were assessed 7-120 days postvaccination with four monovalent mRNA vaccines (n = 494) or subsequent bivalent mRNA-1273.214 vaccination (fifth vaccine) (n = 557). Within 4 months, anti-spike and anti-RBD antibody levels were similar after monovalent and bivalent vaccination in infection-naïve individuals. Hybrid immunity (i.e., vaccination and natural infection) generally increased humoral responses. After bivalent vaccination, compared to monovalent vaccination, residents with hybrid immunity had elevated anti-spike and anti-RBD IgG and IgA antibodies. Omicron BA.1 antibody-mediated neutralization, and CD8+ T cell memory responses to the Omicron BA.1 spike protein, were also higher after bivalent vaccination. Humoral and cellular responses were, therefore, noninferior within 4 months of bivalent mRNA-1273.214 vaccination compared to monovalent mRNA vaccination. Waning of humoral but not cellular immunity was particularly evident in individuals without hybrid immunity. Continued monitoring of vaccine-associated and hybrid immunity against emerging Omicron variants of concern is necessary to assess longevity of protection.


Asunto(s)
COVID-19 , Cuidados a Largo Plazo , Humanos , Anciano , Ontario , Jubilación , SARS-CoV-2/genética , COVID-19/prevención & control , Vacunas de ARNm , Vacunación , Estudios de Cohortes , Inmunoglobulina A , Inmunoglobulina G , Anticuerpos Antivirales , Anticuerpos Neutralizantes
15.
Proc Natl Acad Sci U S A ; 117(36): 21906-21913, 2020 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-32848064

RESUMEN

Development of novel and robust oxygen evolution reaction (OER) catalysts with well-modulated atomic and electronic structure remains a challenge. Compared to the well-known metal hydroxides or (oxyhydr)oxides with lamellar structure, delafossites (ABO2) are characterized by alternating layers of A cations and edge-sharing BO2 octahedra, but are rarely used in OER due to their poor electron conductivity and intrinsic activity. Here, we propose a delafossite analog by mutation of metal oxyhydroxide and delafossite based on first-principles calculations. Modulation on the electronic structure due to distortion of the original crystal field of the BO2 layers is calculated to enhance electron conductivity and catalytic activity. Inspired by the theoretical design, we have experimentally realized the delafossite analog by electrochemical self-reconstruction (ECSR). Operando X-ray absorption spectroscopy and other experimental techniques reveal the formation of delafossite analog with Ag intercalated into bimetallic cobalt-iron (oxyhydr)oxide layers from a metastable precursor through amorphization. Benefitting from the featured local electronic and geometric structures, the delafossite analog shows superior OER activity, affording a current density of 10 mA⋅cm-2 at an overpotential of 187 mV and an excellent stability (300 h) in alkaline conditions.

16.
Angew Chem Int Ed Engl ; 62(15): e202217428, 2023 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-36775803

RESUMEN

Catalytic strategies based on main group metals are significantly less advanced than those of transition metal catalysis, leaving untapped areas of potentially fruitful research. We here demonstrate an effective approach for the modulation of Bi 6p energy levels during the construction of atomically dispersed clusters of amorphous BiOx . Bi oxidation state is proposed to strongly affects the nitrogen fixation activity, with the half-occupied pz orbitals of the Bi2+ ions being highly efficient toward electron injection into the inert N2 molecule. With sufficient catalytic sites to adsorb and activate N2 , the bonding between N2 and catalyst is able to be in situ identified. The catalyst shows an outstanding Faraday efficiency (≈30 %) and high yield (≈113 µg h-1 mg-1 cat ) in NH3 production, outperforming most of the existing catalysts in aqueous solution. These results lay the basis for developing the potential of p-block elements for catalysis of multi-electron reactions.

17.
J Am Chem Soc ; 144(14): 6604-6612, 2022 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-35362968

RESUMEN

Ion migration, hole trapping, and electron-hole recombination are common processes in metal halide perovskites. We demonstrate using ab initio non-adiabatic molecular dynamics and time-domain density functional theory that they are intricately related and strongly influence each other. The hole injection accelerates ion migration by decreasing the diffusion barrier and shortening the migration length. The injected hole also promotes the nonradiative charge recombination by strengthening electron-phonon interactions in the low-frequency region and prolonging the quantum coherence time. The synergy stems from the soft perovskite lattice and response of the valence band maximum to the Pb-I lattice distortion induced by the hole. This work provides important insights into the influence of ion mobility and hole injection on the performance of perovskite solar cells and suggests that high concentration of holes should be avoided.

18.
J Am Chem Soc ; 144(20): 8969-8976, 2022 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-35500303

RESUMEN

The theoretical capacity of a given electrode material is ultimately determined by the number of electrons transferred in each redox center. The design of multi-electron transfer processes could break through the limitation of one-electron transfer and multiply the total capacity but is difficult to achieve because multiple electron transfer processes are generally thermodynamically and kinetically more complex. Here, we report the discovery of two-electron transfer in monolayer Ni(OH)2 nanosheets, which contrasts with the traditional one-electron transfer found in multilayer materials. First-principles calculations predict that the first oxidation process Ni2+ → Ni3+ occurs easily, whereas the second electron transfer in Ni3+ → Ni4+ is strongly hindered in multilayer materials by both the interlayer hydrogen bonds and the domain H structure induced by the Jahn-Teller distortion of the Ni3+ (t2g6eg1)-centered octahedra. In contrast, the second electron transfer can easily occur in monolayers because all H atoms are fully exposed. Experimentally, the as-prepared monolayer is found to deliver an exceptional redox capacity of ∼576 mA h/g, nearly 2 times the theoretical capacity of one-electron processes. In situ experiments demonstrate that monolayer Ni(OH)2 can transfer two electrons and most Ni ions transform into Ni4+ during the charging process, whereas bulk Ni(OH)2 can only be transformed partially. Our work reveals a new redox reaction mechanism in atomically thin Ni(OH)2 nanosheets and suggests a promising path toward tuning the electron transfer numbers to multiply the capacity of the relevant energy storage materials.

19.
J Am Chem Soc ; 144(50): 23223-23229, 2022 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-36490370

RESUMEN

Exploring the transformation/interconversion pathways of catalytic active metal species (single atoms, clusters, nanoparticles) on a support is crucial for the fabrication of high-efficiency catalysts, the investigation of how catalysts are deactivated, and the regeneration of spent catalysts. Sintering and redispersion represent the two main transformation modes for metal active components in heterogeneous catalysts. Herein, we established a novel solid-state atomic replacement transformation for metal catalysts, through which metal atoms exchanged between single atoms and nanoalloys to form a new set of nanoalloys and single atoms. Specifically, we found that the Ni of the PtNi nanoalloy and the Zn of the ZIF-8-derived Zn1 on nitrogen-doped carbon (Zn1-CN) experienced metal interchange to produce PtZn nanocrystals and Ni single atoms (Ni1-CN) at high temperature. The elemental migration and chemical bond evolution during the atomic replacement displayed a Ni and Zn mutual migration feature. Density functional theory calculations revealed that the atomic replacement was realized by endothermically stretching Zn from the CN support into the nanoalloy and exothermically trapping Ni with defects on the CN support. Owing to the synergistic effect of the PtZn nanocrystal and Ni1-CN, the obtained (PtZn)n/Ni1-CN multisite catalyst showed a lower energy barrier of CO2 protonation and CO desorption than that of the reference catalysts in the CO2 reduction reaction (CO2RR), resulting in a much enhanced CO2RR catalytic performance. This unique atomic replacement transformation was also applicable to other metal alloys such as PtPd.

20.
BMC Cancer ; 22(1): 1244, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-36456931

RESUMEN

BACKGROUND: Acid phosphatase type 6 (ACP6) is a mitochondrial lipid phosphate phosphatase that played a role in regulating lipid metabolism and there is still blank in the clinico-pathological significance and functional roles of ACP6 in human cancers. No investigations have been conducted on ACP6 in hepatocellular carcinoma (HCC) up to date. METHODS: Herein, we appraised the clinico-pathological significance of ACP6 in HCC via organizing expression profiles from globally multi-center microarrays and RNA-seq datasets. The molecular basis of ACP6 in HCC was explored through multidimensional analysis. We also carried out in vitro and in vivo experiment on nude mice to investigate the effect of knocking down ACP6 expression on biological functions of HCC cells, and to evaluate the expression variance of ACP6 in xenograft of HCC tissues before and after the treatment of NC. RESULTS: ACP6 displayed significant overexpression in HCC samples (standard mean difference (SMD) = 0.69, 95% confidence interval (CI) = 0.56-0.83) and up-regulated ACP6 performed well in screening HCC samples from non-cancer liver samples. ACP6 expression was also remarkably correlated with clinical progression and worse overall survival of HCC patients. There were close links between ACP6 expression and immune cells including B cells, CD8 + T cells and naive CD4 + T cells. Co-expressed genes of ACP6 mainly participated in pathways including cytokine-cytokine receptor interaction, glucocorticoid receptor pathway and NABA proteoglycans. The proliferation and migration rate of HCC cells transfected with ACP6 siRNA was significantly suppressed compared with those transfected with negative control siRNA. ACP6 expression was significantly inhibited by nitidine chloride (NC) in xenograft HCC tissues. CONCLUSIONS: ACP6 expression may serve as novel clinical biomarker indicating the clinical development of HCC and ACP6 might be potential target of anti-cancer effect by NC in HCC.


Asunto(s)
Fosfatasa Ácida , Carcinoma Hepatocelular , Neoplasias Hepáticas , Animales , Humanos , Ratones , Fosfatasa Ácida/genética , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Ratones Desnudos , ARN Interferente Pequeño
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