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1.
Angew Chem Int Ed Engl ; : e202409515, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39228207

RESUMO

Gallium (Ga) with a low melting point can serve as a unique metallic solvent in the synthesis of intermetallic compounds (IMCs). The negative formation enthalpy of transition metal-Ga IMCs endows them with high catalytic stability. Meanwhile, their tunable crystal structures offer the possibility to tailor the configurations of active sites to meet the requirements for specific catalytic applications. Herein, we present a general method for preparing a range of transition metal-Ga IMCs, including Co-Ga, Ni-Ga, Pt-Ga, Pd-Ga, and Rh-Ga IMCs. The structurally ordered CoGa IMCs with body-centered cubic (bcc) structure are uniformly dispersed on the nitrogen-doped reduced graphene oxide substrate (O-CoGa/NG) and deliver outstanding nitrate reduction reaction (NO3RR) performance, making them excellent catalysts to construct highly efficient rechargeable Zn-NO3- battery. Operando studies and theoretical simulations demonstrate that the electron-rich environments around the Co atoms enhance the adsorption strength of *NO3 intermediate and simultaneously suppress the formation of hydrogen, thus improving the NO3RR activity and selectivity.

2.
Sci Adv ; 10(33): eadp4906, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39141724

RESUMO

High-voltage phase transition constitutes the major barrier to accessing high energy density in layered cathodes. However, questions remain regarding the origin of phase transition, because the interlayer weak bonding features cannot get an accurate description by experiments. Here, we determined van der Waals (vdW) interaction (vdWi) in LixCoO2 via visualizing its electron density, elucidating the origin of O3─O1 phase transition. The charge around oxygen is distorted by the increasing Co─O covalency. The charge distortion causes the difference of vdW gap between O3 and O1 phases, verified by a gap corrected vdW equation. In a high charging state, excessive covalency breaks the vdW gap balance, driving the O3 phase toward a stable O1 one. This interpretation of vdWi-dominated phase transition can be applied to other layered materials, as shown by a map regarding degree of covalence. Last, we introduce the cationic potential to provide a solution for designing high-voltage layered cathodes.

3.
J Agric Food Chem ; 72(36): 19657-19666, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39190007

RESUMO

Magnaporthe oryzae, the causal agent of rice blast, is a fungal disease pathogen. Bacillus spp. have emerged as the most promising biological control agent alternative to chemical fungicides. In this study, the bacterial strain JLU-1 with significant antagonistic activity isolated from the rhizosphere soil of rice was identified as Bacillus velezensis through whole-genome sequencing, average nucleotide identity analysis, and 16S rRNA gene sequencing. Twelve gene clusters for secondary metabolite synthesis were identified in JLU-1. Furthermore, 3 secondary metabolites were identified in JLU-1, and the antagonistic effect of secondary metabolites against fungal pathogens was confirmed. Exposure to JLU-1 reduced the virulence of M. oryzae, and JLU-1 has the ability to induce the reactive oxygen species production of rice and improve the salt tolerance of rice. All of these results indicated that JLU-1 and its secondary metabolites have the promising potential to be developed into a biocontrol agent to control fungal diseases.


Assuntos
Bacillus , Agentes de Controle Biológico , Oryza , Doenças das Plantas , Bacillus/genética , Bacillus/metabolismo , Oryza/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Agentes de Controle Biológico/farmacologia , Agentes de Controle Biológico/metabolismo , Metabolismo Secundário , Antibiose , Microbiologia do Solo , Ascomicetos/genética , Ascomicetos/metabolismo , Controle Biológico de Vetores , Magnaporthe/genética , Magnaporthe/metabolismo
4.
J Int Med Res ; 52(5): 3000605241244743, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38713455

RESUMO

The world population is rapidly aging. Societal aging poses many challenges for individuals, families, nations, and the global healthcare system. Therefore, geriatric care is a crucial issue that demands our attention. In this case report, we describe a woman in her early 70s with multiple comorbidities, polypharmacy, and renal insufficiency who developed cefepime-induced encephalopathy with moderate to severe cerebral dysfunction during treatment of a urinary tract infection. The patient's consciousness level gradually improved, and no further seizures were observed following the discontinuation of cefepime for several days. This case report underscores the fact that polypharmacy and medication safety are significant concerns that are often overlooked when caring for older patients. The report also highlights the increased susceptibility of older individuals to antibiotic-associated adverse reactions during the management of infectious diseases. Therefore, optimization of antibiotic therapy for older patients is a critical issue that requires thorough investigation and consideration in geriatric care.


Assuntos
Antibacterianos , Encefalopatias , Cefepima , Polimedicação , Insuficiência Renal , Infecções Urinárias , Humanos , Cefepima/efeitos adversos , Cefepima/uso terapêutico , Feminino , Idoso , Encefalopatias/induzido quimicamente , Infecções Urinárias/tratamento farmacológico , Insuficiência Renal/induzido quimicamente , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico
5.
J Org Chem ; 89(8): 5491-5497, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38595071

RESUMO

To meet the demand for quillaic acid, a multigram synthesis of quillaic acid was accomplished in 14 steps, starting from oleanolic acid, leading to an overall yield of 3.4%. Key features include C-H activation at C-16 and C-23. Through Pd-catalyzed C-H acetoxylation, the oxidation at C-23 was observed as the major product, as opposed to at C-24. A copper-mediated C-H hydroxylation using O2 successfully afforded the single isomer, 16ß-ol triterpenoid, followed by configuration inversion to the desired 16α-ol compound. In summary, with steps optimized and conducted on a multigram scale, quillaic acid could be feasibly acquired through C-H activation with inexpensive copper catalysts, promoting a more sustainable approach.

6.
Environ Res ; 250: 118444, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38360168

RESUMO

Anthropogenic shifts in seas are reshaping fishing trends, with significant implications for aquatic food sources throughout this century. Examining a 21-year abundance dataset of Argentine shortfin squids Illex argentinus paired with a regional oceanic analysis, we noted strong correlations between squid annual abundance and sea surface temperature (SST) in January and February and eddy kinetic energy (EKE) from March to May in the Southwest Atlantic. A deeper analysis revealed combined ocean-atmosphere interactions, pinpointed as the primary mode in a rotated empirical orthogonal function analysis of SST. This pattern produced colder SST and amplified EKE in the surrounding seas, factors crucial for the unique life stages of squids. Future projections from the CMIP6 archive indicated that this ocean-atmosphere pattern, referred to as the Atlantic symmetric pattern, would persist in its cold SST phase, promoting increased squid abundance. However, rising SSTs due to global warming might counteract the abundance gains. Our findings uncover a previously unrecognized link between squids and specific environmental conditions governed by broader ocean-atmosphere interactions in the Southwest Atlantic. Integrating these insights with seasonal and decadal projections can offer invaluable information to stakeholders in squid fisheries and marine conservation under a changing climate.


Assuntos
Atmosfera , Decapodiformes , Decapodiformes/fisiologia , Animais , Oceano Atlântico , Temperatura , Estações do Ano , Mudança Climática
7.
Nano Lett ; 24(9): 2719-2726, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38377427

RESUMO

Plasmonic Cu@semiconductor heteronanocrystals (HNCs) have many favorable properties, but the synthesis of solid structures is often hindered by the nanoscale Kirkendall effect. Herein, we present the use of an atomically thin Au3Cu palisade interlayer to reduce lattice mismatch and mediate the Kirkendall effect, enabling the successive topological synthesis of Cu@Au3Cu@Ag, Cu@Au3Cu@Ag2S, and further transformed solid Cu@Au3Cu@CdS core-shell HNCs via cation exchange. The atomically thin and intact Au3Cu palisade interlayer effectively modulates the diffusion kinetics of Cu atoms as demonstrated by experimental and theoretical investigations and simultaneously alleviates the lattice mismatch between Cu and Ag as well as Cu and CdS. The Cu@Au3Cu@CdS HNCs feature exceptional crystallinity and atomically organized heterointerfaces between the plasmonic metal and the semiconductor. This results in the efficient plasmon-induced injection of hot electrons from Cu@Au3Cu into the CdS shell, enabling the Cu@Au3Cu@CdS HNCs to achieve high activity and selectivity for the photocatalytic reduction of CO2 to CO.

8.
Genes (Basel) ; 15(2)2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38397226

RESUMO

The LBD family is a plant-specific transcription factor family that plays an important role in a variety of biological processes. However, the function of IbLBD genes in sweet potato remains unclear. In this study, we identified a total of 53 IbLBD genes in sweet potato. Genetic structure showed that most of the IbLBD genes contained only two exons. Following the phylogenetic investigation, the IbLBD gene family was separated into Class I (45 members) and Class II (8) members. Both classes of proteins contained relatively conservative Motif1 and Motif2 domains. The chromosomal locations, gene duplications, promoters, PPI network, and GO annotation of the sweet potato LBD genes were also investigated. Furthermore, gene expression profiling and real-time quantitative PCR analysis showed that the expression of 12 IbLBD genes altered in six separate tissues and under various abiotic stresses. The IbLBD genes belonging to Class I were mostly expressed in the primary root, the pencil root, and the leaves of sweet potatoes, while the genes belonging to Class II were primarily expressed in the various sweet potato roots. The IbLBD genes belonging to Class I were mostly expressed in the primary root, the pencil root, and the leaves of sweet potatoes, while the genes belonging to Class II were primarily expressed in the fibrous root, pencil root, and tuber root.


Assuntos
Ipomoea batatas , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Filogenia , Estresse Fisiológico , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Perfilação da Expressão Gênica
9.
Small ; 20(10): e2302426, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37907412

RESUMO

Tailoring nanoparticles' composition and morphology is of particular interest for improving their performance for catalysis. A challenge of this approach is that the nanoparticles' optimized initial structure often changes during use. Visualizing the three dimensional (3D) structural transformation in situ is therefore critical, but often prohibitively difficult experimentally. Although electron tomography provides opportunities for 3D imaging, restrictions in the tilt range of in situ holders together with electron dose considerations limit the possibilities for in situ electron tomography studies. Here, an in situ 3D imaging methodology is presented using single particle reconstruction (SPR) that allows 3D reconstruction of nanoparticles with controlled electron dose and without tilting the microscope stage. This in situ SPR methodology is employed to investigate the restructuring and elemental redistribution within a population of PtNi nanoparticles at elevated temperatures. The atomic structure of PtNi is further examined and a heat-induced transition is found from a disordered to an ordered phase. Changes in structure and elemental distribution are linked to a loss of catalytic activity in the oxygen reduction reaction. The in situ SPR methodology employed here can be extended to a wide range of in situ studies employing not only heating, but gaseous, aqueous, or electrochemical environments to reveal in-operando nanoparticle evolution in 3D.

10.
J Org Chem ; 88(14): 9946-9958, 2023 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-37410072

RESUMO

3-O-ß-Glucuronide triterpenes are plant-derived compounds. Some of them have been used as herbal medicine and in pharmaceuticals, such as chikusetsu saponins and Quillaja saponins. However, the demand for these materials has remained largely a challenge owing to their natural scarcity and low-yielding purification process. Therefore, a chemical triterpene 3-O-glucuronidation was conducted in this study to alleviate the surging demand on natural source. Various glucuronyl imidate donors and oleanane-type triterpene acceptors were synthesized, and the relative reactivity values (RRV) and acceptor nucleophilic constants (Aka) were systematically measured to study their influence on glucuronidation yield. As a result, applying donors in higher RRV value generally improved the production of 3-O-glucuronide triterpenes. Meanwhile, a bulky pivaloyl group was an ideal 2-O-protection to provide ß-selectivity and prevented side reactions, including orthoester formation and acyl-transfer reaction. Collectively, a positive correlation was observed between reactive donors/acceptors and improved glucuronidation yields. These findings offered insights on the influence of donors' and acceptors' reactivities on 3-O-ß-glucuronide triterpenes synthesis, and this knowledge would help to access saponins of interest to address future needs.


Assuntos
Plantas Medicinais , Saponinas , Triterpenos , Triterpenos/química , Glucuronídeos , Plantas Medicinais/química , Saponinas/química , Extratos Vegetais/química
11.
Intern Emerg Med ; 18(7): 2121-2130, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37253992

RESUMO

People with dementia (PwD) who receive home healthcare (HHC) may have distressing symptoms, complex care needs and high mortality rates. However, there are few studies investigating the determinants of mortality in HHC recipients. To identify end-of-life care needs and tailor individualized care goals, we aim to explore the mortality rate and its determinants among PwD receiving HHC. We conducted a retrospective cohort study using a Taiwanese national population database. People with new dementia diagnosis in 2007-2016 who received HHC were included. We calculated the accumulative mortality rate and applied Poisson regression model to estimate the risk of mortality for each variable (adjusted risk ratios, aRR) with a 95% confidence interval (CI). We included 95,831 PwD and 57,036 (59.5%) of them died during the follow-up period (30.5% died in the first-year). Among comorbidities, cirrhosis was associated with the highest mortality risks (aRR 1.65, 95% CI 1.49-1.83). Among HHC-related factors, higher visit frequency of HHC (> 2 versus ≦1 times/month, aRR 3.52, 95% CI 3.39-3.66) and higher level of resource utilization group (RUG, RUG 4 versus 1, aRR = 1.38, 95% CI 1.25-1.51) were risk factor of mortality risk. Meanwhile, HHC provided by physician and nurse was related to reduced mortality risk (aRR 0.79, 95% CI 0.77-0.81) compared to those provided by nurse only. Anticipatory care planning and timely end-of life care should be integrated in light of the high mortality rate among PwD receiving HHC. Determinants associated with increased mortality risk facilitate the identification of high risk group and tailoring the appropriate care goals. Trial registration number: ClinicalTrials.gov Identifier is NCT04250103 which has been registered on 31st January 2020.


Assuntos
Demência , Serviços de Assistência Domiciliar , Humanos , Estudos de Coortes , Estudos Retrospectivos , Atenção à Saúde , Demência/epidemiologia
12.
J Mol Model ; 29(1): 21, 2022 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-36565386

RESUMO

This experiment was a network pharmacology research based on the theoretical system of traditional Chinese medicine. TCMSP database, PubChem database, RCSB database, and SwissTargetPrediction database were used to study the effective chemical constituents of Ligustri lucidi Fructus and Ecliptae Herba in Erzhiwan, a traditional prescription for nourishing the liver and kidney. Then Genecards database, OMIM database, OMIM Gene Map, and Metascape database were used to study the therapeutic targets of osteoporosis. At last, Cytoscape 3.6.0 software, its built-in Bisogenet and CytoNCA, AutoDockTools-1.5.6 software, PYMOL-2.2.0 software, and Gromacs software, by drawing the relationship diagram between chemical components and disease targets, PPI network of disease, semi-flexible molecular docking technology, evaluation and analysis of enrichment pathway, and molecular dynamics simulation, were used to study the therapeutic mechanism of Erzhiwan on osteoporosis. It is found that the intervention and regulation of Erzhiwan on osteoporosis were mainly realized through multiple targets of active ingredients and multiple pathways, which provided support for the continued development of Erzhiwan.


Assuntos
Medicamentos de Ervas Chinesas , Osteoporose , Humanos , Simulação de Dinâmica Molecular , Simulação de Acoplamento Molecular , Bases de Dados Factuais , Osteoporose/tratamento farmacológico , Tecnologia , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico
13.
Research (Wash D C) ; 2022: 9764976, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36349341

RESUMO

Tunable devices constructed by ferroelectric thin films are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications, for example, resonators, filters, or phase shifters. However, it is difficult to simultaneously achieve these characteristics by traditional strategies, such as doping and strain modifying. Here, we demonstrate that the dielectric tunability of the sol-gel-prepared Pb(Sc1/2Nb1/2)0.9(Mg1/3Nb2/3)0.1O3 (PSNMN) thin film can be almost doubled from ~47% to ~80.0% (at 10 kHz) at a low electric field (~530 kV/cm), and the dielectric loss can be sharply reduced by more than an order of magnitude, from ~0.50 to ~0.037 (at 1 kHz) when the thin film was annealed in air at 650°C for 15 h under the help of an atmosphere-compensating-block (ACB) made from the proto-PSNMN gel. Moreover, the PSNMN thin film annealed with ACB also exhibited an extremely high thermally-stable dielectric tunability in an ultrabroad temperature range (>130 K), which could be attributed to the Maxwell-Wagner (MW) effect generated by the interface between the PSNMN disordered matrix and the B-site nanoscale-ordered structure formed during the long-term annealing process. The reduced dielectric loss is mainly benefited from the reduced concentration of oxygen vacancy and the possible MW effects, and the enhanced dielectric tunability could be ascribed to the weaker domain-pinning effect by oxygen vacancy. The breakthrough provides a new universal strategy to achieve utrahigh tunable performance in A(B'1/2B"1/2)O3 ferroelectric thin films with a B-site nanoscale-ordered structure, meanwhile it paves the way for ultraintergrated tunable thin-film-devices with great phase shifter performance in practical applications.

14.
Adv Mater ; 34(35): e2204363, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35817411

RESUMO

Silicon carbide (SiC), one of the third-generation semiconductor materials with excellent electrical and optoelectronic properties, is ideal for high light-sensing performance. Here, a self-powered SiC ultraviolet (UV) photodetector (PD) is constructed with wider applicability and higher commercialization potential. The great performance of the PD is realized by a remarkable photoinduced dynamic Schottky effect derived from the symbiotic modulation of Schottky and Ohmic contact. Using the pyro-phototronic effect that exists in the N-doped 4H-SiC single crystal PDs, a fast pyroelectric response time of 0.27 s is achieved, which is almost ten times shorter than that obtained from the steady-state signal under UV illumination. The maximal transient photoresponsivity reaches 9.12 nA mW-1 , which is ≈20% higher than the conventional photoelectric signal. Moreover, different regions of the 4H-SiC centimeter-scale chip output distinct signals under UV illumination, demonstrating efficient optical imaging and information transmission capabilities of this device. This work not only reveals the fundamental optoelectronic physics lying in this vital third-generation semiconductor, but also sheds light on its potential photosensing applications for large-scale commercialization.

15.
Inorg Chem ; 61(9): 3989-3996, 2022 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-35191681

RESUMO

Engineering the structure of core-shell colloidal semiconductor nanoparticles (CSNPs) is attractive due to the potential to enhance photo-induced charge transfer and induce favorable optical and electronic properties. Nonetheless, the sensitivity of telluride CSNPs to high temperatures makes it challenging to precisely modulate their surface crystallinity. Herein, we have developed an efficient strategy for synthesizing telluride CSNPs with thin amorphous shells using aqueous cation exchange (ACE). By changing the synthesis temperature in the range of 40-110 °C, the crystallinity of the CdTe nanoparticles was controllable from perfect crystals with no detectable amorphous shell (c-CdTe) to a core-shell structure with a crystalline CdTe NP core covered by an amorphous shell of tunable thickness up to 7-8 nm (c@a-CdTe). A second ACE step transformed c@a-CdTe to crystalline CdTe@HgTe core-shell NPs. The c@a-CdTe nanoparticles synthesized at 60 °C and having a 4-5 nm thick amorphous shell exhibited the highest surface-enhanced Raman scattering activity with a high enhancement factor around 8.82 × 105, attributed to the coupling between the amorphous shell and the crystalline core.

16.
Ultramicroscopy ; 235: 113498, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35217410

RESUMO

Scanning transmission electron microscopy (STEM) tomography is widely used to reveal three-dimensional (3D) structure of the specimens from nanometers to atomic resolution. Advances in transmission electron microscope enable high resolution and low dose data acquisition for 3D reconstruction to resolve 3D coordinates of single atoms. Meanwhile, the developments of reconstruction algorithms increase the reconstruction quality. However, the as-acquired raw datasets often require alignments before they can be used as inputs to feed a reconstruction algorithm. The effect of post-acquisition data misalignments on the final reconstruction quality of STEM tomography is less discussed. Here, using phantom datasets with a focus on atomic features, we simulate a range of misalignments on each alignment step and correlate the level of misalignments to the final reconstruction quality. The study pinpoints that accurate alignments of tilt angles and stack positions and minimizing scan distortion are important to the reconstruction quality, while the sequence of alignment steps do not affect the reconstruction quality. The study not only emphasizes the most important alignment steps that should be pay attention to for a high-quality 3D reconstruction, but also summarizes post-acquisition data alignment procedures as a primer for new practitioners to use STEM tomography.


Assuntos
Tomografia com Microscopia Eletrônica , Processamento de Imagem Assistida por Computador , Algoritmos , Tomografia com Microscopia Eletrônica/métodos , Processamento de Imagem Assistida por Computador/métodos , Imagens de Fantasmas
18.
Nat Mater ; 20(12): 1677-1682, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34446864

RESUMO

The physical properties of clays and micas can be controlled by exchanging ions in the crystal lattice. Atomically thin materials can have superior properties in a range of membrane applications, yet the ion-exchange process itself remains largely unexplored in few-layer crystals. Here we use atomic-resolution scanning transmission electron microscopy to study the dynamics of ion exchange and reveal individual ion binding sites in atomically thin and artificially restacked clays and micas. We find that the ion diffusion coefficient for the interlayer space of atomically thin samples is up to 104 times larger than in bulk crystals and approaches its value in free water. Samples where no bulk exchange is expected display fast exchange at restacked interfaces, where the exchanged ions arrange in islands with dimensions controlled by the moiré superlattice dimensions. We attribute the fast ion diffusion to enhanced interlayer expandability resulting from weaker interlayer binding forces in both atomically thin and restacked materials. This work provides atomic scale insights into ion diffusion in highly confined spaces and suggests strategies to design exfoliated clay membranes with enhanced performance.

19.
Artigo em Inglês | MEDLINE | ID: mdl-34360410

RESUMO

BACKGROUND: People with dementia are a high-risk group for hip fractures. Although the increased risk of hip fractures associated with antipsychotic drugs (APD) is found in older populations, little is known about the risk for people with dementia living in Asia. We aimed to investigate the association between hip fractures and the characteristics of APD use in patients with dementia. METHODS: A nested case-control analysis was conducted on a nationwide cohort in Taiwan. People with diagnoses of dementia during 2003-2012 were identified. Conditional logistic regression analysis was performed, and adjusted odds ratios (aORs) were calculated with a 95% confidence interval (CI) to estimate the risk of hip fractures. RESULTS: APD use was associated with an increased risk of hip fractures in patients with dementia; current use or combined use of first and second generations of APDs had even higher risks. Regarding the duration of APD use, a U-shape curve of hip fracture risk was noted, and the risk peaked during 0-15 days and >215 days of exposure (aOR = 1.46, 95% CI 1.37-1.57; aOR = 1.47, 95% CI 1.37-1.58; respectively). Considering the doses of APDs, the hip fracture risk was significantly increased with all four levels of the cumulative doses and average daily doses and peaked in the group with the highest average daily dose. CONCLUSIONS: The findings suggest that caution must be taken when initiating APD use in patients with dementia, even in a small dose, and mixed types of APD prescriptions should be administered with care. Furthermore, frequent evaluation of the possibility of tapering or withdrawal of the medication is necessary, as the risk does not attenuate after long-term use.


Assuntos
Demência , Fraturas do Quadril , Preparações Farmacêuticas , Idoso , Estudos de Casos e Controles , Demência/induzido quimicamente , Demência/epidemiologia , Fraturas do Quadril/induzido quimicamente , Fraturas do Quadril/epidemiologia , Humanos , Fatores de Risco
20.
Nano Lett ; 21(9): 3989-3996, 2021 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-33899489

RESUMO

We report a rapid solution-phase strategy to synthesize alloyed PtNi nanoparticles which demonstrate outstanding functionality for the oxygen reduction reaction (ORR). This one-pot coreduction colloidal synthesis results in a monodisperse population of single-crystal nanoparticles of rhombic dodecahedral morphology with Pt-enriched edges and compositions close to Pt1Ni2. We use nanoscale 3D compositional analysis to reveal for the first time that oleylamine (OAm)-aging of the rhombic dodecahedral Pt1Ni2 particles results in Ni leaching from surface facets, producing aged particles with concave faceting, an exceptionally high surface area, and a composition of Pt2Ni1. We show that the modified atomic nanostructures catalytically outperform the original PtNi rhombic dodecahedral particles by more than two-fold and also yield improved cycling durability. Their functionality for the ORR far exceeds commercially available Pt/C nanoparticle electrocatalysts, both in terms of mass-specific activities (up to a 25-fold increase) and intrinsic area-specific activities (up to a 27-fold increase).

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