Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 133
Filtrar
1.
Development ; 149(6)2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35299237

RESUMO

The vertebrate body is built during embryonic development by the sequential addition of new tissue as the embryo grows at its caudal end. During this process, progenitor cells within the neuromesodermal competent (NMC) region generate the postcranial neural tube and paraxial mesoderm. Here, we have applied a genetic strategy to recover the NMC cell population from mouse embryonic tissues and have searched their transcriptome for cell-surface markers that would give access to these cells without previous genetic modifications. We found that Epha1 expression is restricted to the axial progenitor-containing areas of the mouse embryo. Epha1-positive cells isolated from the mouse tailbud generate neural and mesodermal derivatives when cultured in vitro. This observation, together with their enrichment in the Sox2+/Tbxt+ molecular phenotype, indicates a direct association between Epha1 and the NMC population. Additional analyses suggest that tailbud cells expressing low Epha1 levels might also contain notochord progenitors, and that high Epha1 expression might be associated with progenitors entering paraxial mesoderm differentiation. Epha1 could thus be a valuable cell-surface marker for labeling and recovering physiologically active axial progenitors from embryonic tissues.


Assuntos
Padronização Corporal , Mesoderma , Animais , Padronização Corporal/genética , Diferenciação Celular/genética , Mesoderma/metabolismo , Camundongos , Medula Espinal , Células-Tronco
2.
Proc Natl Acad Sci U S A ; 119(20): e2202202119, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35533280

RESUMO

SignificanceIn recent years, lithium-ion batteries (LIBs) have been widely applied in electric vehicles as energy storage devices. However, it is a great challenge to deal with the large number of spent LIBs. In this work, we employ a rapid thermal radiation method to convert the spent LIBs into highly efficient bifunctional NiMnCo-activated carbon (NiMnCo-AC) catalysts for zinc-air batteries (ZABs). The obtained NiMnCo-AC catalyst shows excellent electrochemical performance in ZABs due to the unique core-shell structure, with face-centered cubic Ni in the core and spinel NiMnCoO4 in the shell. This work provides an economical and environment-friendly approach to recycling the spent LIBs and converting them into novel energy storage devices.

3.
Small ; 20(38): e2400762, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38794872

RESUMO

Single-crystal lithium-nickel-manganese-cobalt-oxide (SC-NMC) is attracting increasing attention due to its excellent structural stability. However, its practical production faces challenges associated with complex precursor preparation processes and severe lithium-nickel cation mixing at high temperatures, which restricts its widespread application. Here, a molten-salt-assisted method is proposed using low-melting-point carbonates. This method obviates the necessity for precursor processes and simplified the synthetic procedure for SC-NMC down to a single isothermal sintering step. Multiple characterizations indicate that the acquired SC-LiNi0.6Mn0.2Co0.2O2 (SC-622) exhibits favorable structural capability against intra-granular fracture and suppressive Li+/Ni2+ cation mixing. Consequently, the SC-622 exhibits superior electrochemical performance with a high initial specific capacity (174 mAh g-1 at 0.1 C, 3.0-4.3 V) and excellent capacity retention (87.5% after 300 cycles at 1C). Moreover, this molten-salt-assisted method exhibits its effectiveness in directly regenerating SC-622 from spent NMC materials. The recovered material delivered a capacity of 125.4 mAh g-1 and retained 99.4% of the initial capacity after 250 cycles at 1 C. This work highlights the importance of understanding the process-structure-property relationships and can broadly guide the synthesis of other SC Ni-rich cathode materials.

4.
Small ; 20(42): e2401610, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38856970

RESUMO

Herein, the design of novel and safe electrolyte formulations for high-voltage Ni-rich cathodes is reported. The solvent mixture comprising 1,1,2,2-tetraethoxyethane and propylene carbonate not only displays good transport properties, but also greatly enhances the overall safety of the cell thanks to its low flammability. The influence of the conducting salts, that is, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium bis(fluorosulfonyl)imide (LiFSI), and of the additives lithium bis(oxalato)borate (LiBOB) and lithium difluoro(oxalato)borate (LiDFOB) is examined. Molecular dynamics simulations are carried out to gain insights into the local structure of the different electrolytes and the lithium-ion coordination. Furthermore, special emphasis is placed on the film-forming abilities of the salts to suppress the anodic dissolution of the aluminum  current collector and to create a stable cathode electrolyte interphase (CEI). In this regard, the borate-based additives significantly alleviate the intrinsic challenges associated with the use of LiTFSI and LiFSI salts. It is worth remarking that a superior cathode performance is achieved by using the LiFSI/LiDFOB electrolyte, displaying a high specific capacity of 164 mAh g-1 at 6 C and ca. 95% capacity retention after 100 cycles at 1 C. This is attributed to the rich chemistry of the generated CEI layer, as confirmed by ex situ X-ray photoelectron spectroscopy.

5.
Small ; 20(34): e2312059, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38600893

RESUMO

Realizing high-performance thick electrodes is considered as a practical strategy to promote the energy density of lithium-ion batteries. However, establishing effective transport pathways for both lithium-ions and electrons in a thick electrode is very challenging. This study develops a hierarchical conductive network structure for constructing high-performance NMC811 (LiNi0.8Mn0.1Co0.1O2) cathode toward stable cycling at high areal mass loadings. The hierarchical conductive networks are composed of a Li+/e- mixed conducting interface (lithium polyacrylate/hydroxyl-functionalized multiwalled carbon nanotubes) on NMC811 particles, and a segregated network of single-walled carbon nanotubes in the electrode, without any additional binders or carbon black. Such strategy endows the NMC811 cathode (up to 250 µm and 50 mg cm-2) with low porosity/tortuosity, ultrahigh Li+/e- conductivities and excellent mechanical property at low carbon nanotube content (1.8 wt%). It significantly improves the electrochemical reaction homogeneity along the electrode depth, meanwhile effectively inhibits the side reactions at the electrode/electrolyte interface and cracks in the NMC particles during cycling. This work emphasizes the crucial role of the electronic/ionic cooperative transportation in the performance deterioration of thick cathodes, and provide guidance for architecture optimization and performance improvement of thick electrodes toward practical applications, not just for the NMC811 cathode.

6.
Small ; : e2405432, 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39295569

RESUMO

LiNi0.8Mn0.1Co0.1O2 (NMC811) is the most promising cathode material for future Li-ion batteries (LIBs). However, the bulk and surface structural instabilities retard its commercial success. Surface chemical instability toward exposure to moisture (H2O and CO2) leads to the formation of residual lithium compounds (RLCs: Li2CO3, LiOH) on the surface. The alkaline RLCs form a resistive layer on the surface of NMC811 by undergoing parasitic side reactions with electrolytes. Herein, an "Adverse-to-Beneficial" approach is proposed to eliminate RLCs by chemically transforming them into a LixPOy (Li3PO4 and LiPO3) interface. The interface protects the NMC811 surface from moisture attack and unwanted side reactions with electrolytes. It enhances the cycle life by retaining 70% of the initial capacity after 300 cycles at a 0.5C rate and 60% after 500 cycles, even at a 5C rate in a voltage window of 3.0-4.3 V versus Li+/Li. The coexistence of two Li-conducting phases lowers the voltage polarization of the kinetically sluggish H1 → M phase transition to unlock fast cycling, reduces cationic disorder, improves coulombic efficiency, enhances ion diffusion kinetics, and minimizes particle crack formation after long-term cycling. Hence, the LixPOy interface yields multifaceted benefits in the storage, processing, and electrochemistry of NMC811.

7.
Small ; : e2406058, 2024 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-39439164

RESUMO

Increasing the thickness of the electrodes is considered the primary strategy to elevate battery energy density. However, as the thickness increases, rate performance, cycling performance, and mechanical stability are affected due to the sluggish ion transfer kinetics and compromised structural integrity. Inspired by the natural hierarchical porous structure of trees, electrodes with bioinspired architecture are fabricated to address these challenges. Specifically, electrodes with aligned columns consist of tree-inspired vertical channels, and hierarchical pores are constructed by screen printing and ice-templating, imparting enhanced electrochemical and mechanical performance. Employing an aqueous-based binder, the LiNi0.8Mn0.1Co0.1O2 cathode achieves a high areal energy density of 15.1 mWh cm-2 at a rate of 1C at mass loading of 26.0 mg cm-2, benefitting from the multiscale pores that elevated charge transfer kinetics in the thick electrode. The electrodes demonstrate capacity retention of 90% at the 100th cycle at a high current density of 5.2 mA cm-2. To understand the mechanisms that promote electrode performance, simplified electro-chemo-mechanical models are developed, the drying process and the charge-discharge process are simulated. The simulation results suggested that the improved performance of the designed electrode benefits from the lower ohmic overpotential and less strain gradient and stress concentration due to the hierarchical porous architecture.

8.
J Environ Manage ; 366: 121710, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38986378

RESUMO

We report an environmentally benign recycling approach for large-capacity nickel manganese cobalt (NMC) batteries through the electrochemical concentration of lithium on the anode and subsequent recovery with only water. Cycling of the NMC pouch cells indicated the potential for maximum lithium recovery at a 5C charging rate. The anodes extracted from discharged and disassembled cells were submerged in deionized water, resulting in lithium dissolution and graphite recovery from the copper foils. A maximum of 13 mg of lithium salts per 100 mg of the anode, copper current collector, and separator was obtained from NMC pouch cell cycled at a 4C charging rate. The lithium salts extracted from batteries cycled at low C-rates were richer in lithium carbonate, while the salts from batteries cycled at high C-rates were richer in lithium oxides and peroxides, as determined by X-Ray photoelectron spectroscopy. The present method can be successfully used to recover all the pouch cell components: lithium, graphite, copper, and aluminum current collectors, separator, and the cathode active material.


Assuntos
Fontes de Energia Elétrica , Lítio , Lítio/química , Água/química , Eletrodos , Solventes/química , Cobalto/química , Reciclagem , Níquel/química , Manganês/química , Grafite/química , Cobre/química
9.
Health Promot Pract ; : 15248399241240431, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38533745

RESUMO

Digital technology creates new opportunities to design multisensory learning experiences. Evidence suggests that digital innovation can greatly benefit health education, including nutrition programs. The COVID-19 pandemic disrupted the education sector, forcing schools to modify standard practices from exclusively in-person delivery to online or blended learning. Digitalized curriculums became particularly useful as an Emergency Remote Teaching tool. This article focuses on developing and implementing a multimedia, multisensory, and scalable Hip-Hop Healthy Eating and Living in Schools (H.E.A.L.S.) Nutrition-Math Curriculum (NMC). NMC comprises 20 lessons-music-based multimedia resources used in the classroom or at home. Fourteen lessons represent self-directed online modules (asynchronous learning) hosted on a Learning Management System (LMS) called "Gooru." The remaining six lessons are teacher-facilitated (in person or using Zoom) review sessions (synchronous learning). The article discusses (1) the development of NMC through the lens of the Multisensory Multilevel Health Education Model (MMHEM), (2) the high acceptability of NMC evaluated using a mixed-methods design among minoritized fifth-grade students attending an after-school program, and (3) the students' completion and mastery rates of the NMC modules based on LMS data. Multimedia nutrition education programs integrated with common core curriculum content, such as NMC, may be a promising avenue for disseminating health education to minoritized children living in New York City and similar high fast-food density cities.

10.
Br J Community Nurs ; 29(4): 160-161, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38564445

RESUMO

In this month's Policy column, Iwan Dowie explores the laws of confidentiality, which forms part of the legal obligation of every community nurse.


Assuntos
Confidencialidade , Humanos
11.
Antimicrob Agents Chemother ; 67(5): e0007823, 2023 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-37039645

RESUMO

The in vitro activity of imipenem-relebactam, meropenem-vaborbactam, ceftazidime-avibactam, and cefiderocol was evaluated against both clinical and isogenic enterobacterial isolates producing carbapenemases of the SME, NmcA, FRI, and IMI types. Ceftazidime-avibactam and meropenem-vaborbactam showed the highest activity against all tested isolates; imipenem-relebactam showed only moderate activity. All isolates remained susceptible to cefiderocol. Furthermore, avibactam and vaborbactam have greater inhibitory activity than relebactam against the tested carbapenemases. Overall, ceftazidime-avibactam, meropenem-vaborbactam, and cefiderocol were the most effective therapeutic options for treating infections caused by the tested minor carbapenemase producers.


Assuntos
Lactamas , Inibidores de beta-Lactamases , Inibidores de beta-Lactamases/farmacologia , Inibidores de beta-Lactamases/uso terapêutico , Meropeném/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Ceftazidima/farmacologia , Compostos Azabicíclicos/farmacologia , beta-Lactamases/genética , Imipenem/farmacologia , Combinação de Medicamentos , Testes de Sensibilidade Microbiana , Cefiderocol
12.
Nano Lett ; 22(3): 1278-1286, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35041789

RESUMO

The isostructural nature of Li-layered cathodes allows for accommodating multiple transition metals (TMs). However, little is known about how the local TM stoichiometry influences the charging behavior of battery particles thus impacting battery performance. Here, we develop heterogeneous compositional distributions in polycrystalline LiNi1-x-yMnxCoyO2 (NMC) particles to investigate the interplay between local stoichiometry and charge distribution. These NMC particles exhibit a broad, continuous distribution of local Ni/Mn/Co stoichiometry, which does not compromise the global layeredness. The local Mn and Ni concentrations in individual NMC particles are positively and negatively correlated with the electrochemically induced Ni oxidation, respectively, whereas the Co concentration does not impose a clear effect on the Ni oxidation. The resulting material delivers excellent reversible capacity, rate capability, and cycle life at high operating voltages. Engineering Ni/Mn/Co distribution in NMC particles may provide a path toward controlling the charge distribution and thus chemomechanical properties of polycrystalline battery particles.

13.
Nano Lett ; 22(14): 5883-5890, 2022 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-35797382

RESUMO

The composition dynamics regulate the accessible capacity and rate performance of rechargeable batteries. Heterogeneous Li reactions can lead to nonuniform electrochemical activities and amplify mechanical damage in the cell. Here, we employ operando optical microscopy as a laboratory tool to map the spatial composition heterogeneity in a solid-solution cathode for Li-ion batteries. The experiments are conducted at slow charging conditions to investigate the thermodynamic origins. We observe that the active particles charge asynchronously with reaction fronts propagating on the particle surfaces during the first charge, while subsequent (dis)charge cycles transition to a synchronous behavior for the same group of particles. Such transition is understood by computational modeling, which incorporates the dependence of Li diffusivity and interfacial reaction rate on the state of charge. The optical experiments and theoretical modeling provide insight into the reaction heterogeneity of porous electrodes and electrochemical conditioning for layered oxide cathodes.

14.
Angew Chem Int Ed Engl ; 62(50): e202313437, 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-37931064

RESUMO

While it is widely recognized that the operating temperature significantly affects the energy density and cycle life of lithium-ion batteries, the consequence of electrode-electrolyte interphase chemistry to sudden environmental temperature changes remains inadequately understood. Here, we systematically investigate the effects of a temperature pulse (T pulse) on the electrochemical performance of LiNi0.8 Mn0.1 Co0.1 O2 (NMC811) pouch full cells. By utilizing advanced characterization tools, such as time-of-flight secondary-ion mass spectrometry, we reveal that the T pulse can lead to an irreversible degradation of cathode-electrolyte interphase chemistry and architecture. Despite negligible immediate impacts on the solid-electrolyte interphase (SEI) on graphite anode, aggregated cathode-to-anode chemical crossover gradually degrades the SEI by catalyzing electrolyte reduction decomposition and inducing metallic dead Li formation because of insufficient cathode passivation after the T pulse. Consequently, pouch cells subjected to the T pulse show an inferior cycle stability to those free of the T pulse. This work unveils the effects of sudden temperature changes on the interphase chemistry and cell performance, emphasizing the importance of a proper temperature management in assessing performance.

15.
Small ; 18(12): e2105833, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35060327

RESUMO

Ni-rich layered LiNix Mny Co1- x - y O2 (NMCs, x ≥ 0.8) are poised to be the dominating cathode materials for lithium-ion batteries for the foreseeable future. Conventional polycrystalline NMCs, however, suffer from severe cracking along the grain boundaries of primary particles and capacity loss under high charge and/or discharge rates, hindering their implementation in fast-charging electric vehicular (EV) batteries. Single-crystal (SC) NMCs are attractive alternatives as they eliminate intergranular cracking and allow for grain-level surface optimization for fast Li transport. In the present study, the authors report synthetic approaches to produce SC LiNi0.8 Co0.1 Mn0.1 O2 (NMC811) samples with different morphologies: Oct-SC811 with predominating (012)-family surface and Poly-SC811 with predominating (104)-family surface. Poly-SC811, representing the first experimentally synthesized NMC811 single crystals with (104) surface, delivers superior performance even at the ultra-high rate of 6 C. Through detailed X-ray analysis and electron microscopy characterization, it is shown that the enhanced performance originates from better chemical and structural stabilities, faster Li+ diffusion kinetics, suppressed side reactions with electrolyte, and excellent cracking resistance. These insights provide important design guidelines in the future development of fast-charging NMC-type cathode materials.

16.
Small ; 18(7): e2104625, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34882972

RESUMO

High-Ni-rich layered oxides [e.g., LiNix Coy Mnz O2 ; x > 0.5, x + y + z = 1] are considered one of the most promising cathodes for high-energy-density lithium-ion batteries (LIB). However, extreme electrode-electrolyte reactions, several interfacial issues, and structural instability restrict their practical applicability. Here, a shortened unconventional atomic surface reduction (ASR) technique is demonstrated on the cathode surface as a derivative of the conventional atomic layer deposition (ALD) process, which brings superior cell performances. The atomic surface reaction (reduction process) between diethyl-zinc (as a single precursor) and Ni-rich NMC cathode [LiNi0.8 Co0.1 Mn0.1 O2 ; NCM811] material is carried out using the ALD reactor at different temperatures. The temperature dependency of the process through advanced spectroscopy and microscopy studies is demonstrated and it is shown that thin surface film is formed at 100 °C, whereas at 200 °C a gradual atomic diffusion of Zn ions from the surface to the near-surface regions is taking place. This unique near-surface penetration of Zn ions significantly improves the electrochemical performance of the NCM811 cathode. This approach paves the way for utilizing vapor phase deposition processes to achieve both surface coatings and near-surface doping in a single reactor to stabilize high-energy cathode materials.

17.
Entropy (Basel) ; 24(8)2022 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-36010702

RESUMO

Non-malleable codes are a natural relaxation of error correction and error detection codes applicable in scenarios where error-correction or error-detection is impossible. Over the last decade, non-malleable codes have been studied for a wide variety of tampering families. Among the most well studied of these is the split-state family of tampering channels, where the codeword is split into two or more parts and each part is tampered with independently. We survey various constructions and applications of non-malleable codes in the split-state model.

18.
Angew Chem Int Ed Engl ; 61(35): e202205967, 2022 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-35789166

RESUMO

LiNix Coy Mnz O2 (x+y+z=1)||graphite lithium-ion battery (LIB) chemistry promises practical applications. However, its low-temperature (≤ -20 °C) performance is poor because the increased resistance encountered by Li+ transport in and across the bulk electrolytes and the electrolyte/electrode interphases induces capacity loss and battery failures. Though tremendous efforts have been made, there is still no effective way to reduce the charge transfer resistance (Rct ) which dominates low-temperature LIBs performance. Herein, we propose a strategy of using low-polarity-solvent electrolytes which have weak interactions between the solvents and the Li+ to reduce Rct , achieving facile Li+ transport at sub-zero temperatures. The exemplary electrolyte enables LiNi0.8 Mn0.1 Co0.1 O2 ||graphite cells to deliver a capacity of ≈113 mAh g-1 (98 % full-cell capacity) at 25 °C and to remain 82 % of their room-temperature capacity at -20 °C without lithium plating at 1/3C. They also retain 84 % of their capacity at -30 °C and 78 % of their capacity at -40 °C and show stable cycling at 50 °C.

19.
Nano Lett ; 20(3): 1607-1613, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32017575

RESUMO

We present the first results of in situ scanning electron microscopy (SEM) of an all-solid Li battery with a nickel-manganese-cobalt-oxide (NMC-622) cathode at 50 °C and an operating voltage of 2.7-4.3 V. Experiments were conducted under a constant current at several C rates (nC rate: cycling in 1/n h): C/12, C/6, and C/3. The microstructure evolution during cycling was monitored by continuous secondary electron imaging. We found that the chemical degradation of the solid polymer electrolyte (SPE) was the main mechanism for battery failure. This degradation was observed in the form of a gradual thinning of the SPE as a function of cycling time, resulting in gas generation from the cell. We also present various dynamic electrochemical and mechanical phenomena, as observed by SEM images, and compare the performance of this battery with that of an all-solid Li battery with a LiFePO4 cathode.

20.
Adv Exp Med Biol ; 1232: 11-17, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893388

RESUMO

In the adult brain, it is well known that increases in local neural activity trigger changes in regional blood flow and, thus, changes in cerebral energy metabolism. This regulation mechanism is called neurovascular coupling (NVC). It is not yet clear to what extent this mechanism is present in the premature brain. In this study, we explore the use of transfer entropy (TE) in order to compute the nonlinear coupling between changes in brain function, assessed by means of EEG, and changes in brain oxygenation, assessed by means of near-infrared spectroscopy (NIRS). In a previous study, we measured the coupling between both variables using a linear model to compute TE. The results indicated that changes in brain oxygenation were likely to precede changes in EEG activity. However, using a nonlinear and nonparametric approach to compute TE, the results indicate an opposite directionality of this coupling. The source of the different results provided by the linear and nonlinear TE is unclear and needs further research. In this study, we present the results from a cohort of 21 premature neonates. Results indicate that TE values computed using the nonlinear approach are able to discriminate between neonates with brain abnormalities and healthy neonates, indicating a less functional NVC in neonates with brain abnormalities.


Assuntos
Encéfalo , Acoplamento Neurovascular , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Encéfalo/fisiopatologia , Encefalopatias/diagnóstico , Encefalopatias/fisiopatologia , Eletroencefalografia , Entropia , Humanos , Recém-Nascido , Acoplamento Neurovascular/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA