Ionic liquids (ILs) are promising materials for application in a new generation of Li-batteries. They can be used as electrolyte, interlayer, or incorporated into other materials. ILs have ability to form a stable Solid Electrochemical Interface (SEI) which plays an important role, preventing Li-based electrode from oxidation and electrolyte from extensive decomposition. Experimentally, it is hardly possible to elicit fine details of the SEI structure. To remedy this situation, we have performed a comprehensive computational study (DFT-MD) to determine the composition and structure of the SEI compact layer formed between Li anode and [Pyr14][TFSI] IL. We found that the [TFSI] anions quickly reacted with Li and decomposed, unlike the [Pyr14] cations which remained stable. The obtained SEI compact layer structure is non-homogeneous and consists of the atomized S, N, O, F, and C anions oxidized by Li atoms.
We describe herein an adsorption-induced energy transfer between phenanthrene, a major environmental pollutant, and a fluorescently labeled dendrimer acting as a host molecule. We find experimentally that such energy transfer is the most efficient at a solvent pH of 8 and for a phenanthrene:dendrimer molar ratio of 1:2. Using molecular dynamics simulations we show that the strongest binding interactions occur between phenanthrene and the primary amines of the dendrimer. The simulations provide evidence that at low pH, phenanthrene-phenanthrene interactions are favorable and compete with phenanthrene-dendrimer binding. This study offers a new scheme for detecting dendrimer molecular assembly and a physical basis for exploiting dendrimer nanotechnologies for water purification and environmental remediation.
For decades, the glial function has been highlighted not only as the ‘structural glue’, but also as an ‘active participant’ in neural circuits. Here, we suggest that tumor necrosis factor α (TNF-α), a key inflammatory cytokine, alters the neural activity of the cerebellar Purkinje cells (PCs) by facilitating gliotransmission in the juvenile male rat cerebellum. A bath application of TNF-α (100 ng/ml) in acute cerebellar slices elevates spiking activity of PCs with no alterations in the regularity of PC firings. Interestingly, the effect of TNF-α on the intrinsic excitability of PCs was abolished under a condition in which the type1 TNF receptor (TNFR1) in Bergmann glia (BG) was genetically suppressed by viral delivery of an adeno-associated virus (AAV) containing TNFR1-shRNA. In addition, we measured the concentration of glutamate derived from dissociated cerebellar cortical astrocyte cultures treated with TNF-α and observed a progressive increase of glutamate in a time-dependent manner. We hypothesised that TNF-α-induced elevation of glutamate from BGs enveloping the synaptic cleft may directly activate metabotropic glutamate receptor1 (mGluR1). Pharmacological inhibition of mGluR1, indeed, prevented the TNF-α-mediated elevation of the intrinsic excitability in PCs. Taken together, our study reveals that TNF-α triggers glutamate release in BG, thereby increasing the intrinsic excitability of cerebellar PCs in a mGluR1-dependent manner.
Dendrimers have been widely used as nanostructured carriers for guest species in a variety of applications in medicine, catalysis, and environmental remediation. Theory and simulation methods are an important complement to experimental approaches that are designed to develop a fundamental understanding about how dendrimers interact with guest molecules. This review focuses on computational studies aimed at providing a better understanding of the relevant physicochemical parameters at play in the binding and release mechanisms between polyamidoamine (PAMAM) dendrimers and guest species. We highlight recent contributions that model supramolecular dendrimer-guest complexes over the temporal and spatial scales spanned by simulation methods ranging from all-atom molecular dynamics to statistical field theory. The role of solvent effects on dendrimer-guest interactions and the importance of relating model parameters across multiple scales is discussed.
energy density (372 mAh g −1 ), which is not sufficient to meet the increasing energy density demand for electric vehicles, portable electronic devices, and large-scale energy storage systems. [4,5] This motivates reviving Li-metal as a prospective anode material that could provide more than tenfold higher capacity (3860 mAh g −1 ), low electrochemical potential (−3.04 V vs the standard hydrogen electrode, SHE), and low gravimetric density (0.534 g cm −3 ). [6,7] These advantages make application of Li anode batteries indispensable for next generation energy-storage devices, such as Li-S and Li-air batteries.Despite the great potential of high energy density batteries, commercialization of Li-metal batteries (LMBs) is hindered by poor cycling performance and severe safety issues originating from the high reactivity of Limetal. [7] In addition to dendrite growth, Li reacts instantaneously with electrolytes, resulting in formation of a chemically unstable and mechanically fragile surface film referred to as the solid electrolyte interphase (SEI). [8,9] Since the SEI plays an important role in battery stability and performance, extensive research has been conducted to investigate and improve SEI properties, including optimization of electrolyte compositions, [10] application of solid electrolytes, [11] and construction of artificial SEI layers. [12] In addition, significant efforts have been made to investigate the SEI compositions and morphology using such techniques as X-ray photo electron spectroscopy, [13] mass spectrometry, [14] and nuclear magnetic resonance. [15] However, the atomistic structure and properties of the electrode/ electrolyte interface, particularly the evolution of SEI growth, remain poorly understood. The complexity of the chemical and electrochemical reactions at the interface makes it most difficult to carry out direct experimental measurements of the SEI formation process beyond chemical composition to provide the detailed information needed to develop improved materials and devices.Given the great difficulties for experimental assessment of the atomistic details of the SEI, we have applied quantum mechanics (QM) based molecular dynamics (MD) approaches to provide fundamental information about the reactions at the interface between Li-metal and electrolyte molecules at the atomistic level. [16][17][18] However such QM studies are generally limited to <300 atoms and <100 picoseconds (ps) due to extremely high computational costs, limiting applications of QM-MD to very simplistic studies at the 2-3 nm scale of the The solid electrolyte interphase (SEI) forms on electrode surfaces from decomposition of the electrolyte. However, there is almost no atomistic detail of SEI formation on Li metal anode, a major obstacle in understanding the highly complex battery electrochemistry sufficiently to design high performance batteries. Herein, a realistic atomistic model (39 000 atoms) for the SEI formation at the interface between the Li metal anode and ionic liquid electrolyte using reactive molecular ...
Climbing fibers (CFs) generate complex spikes (CS) and Ca2+ transients in cerebellar Purkinje cells (PCs), serving as instructive signals. The so-called 'all-or-none' character of CSs has been questioned since the CF burst was described. Although recent studies have indicated a sensory-driven enhancement of PC Ca2+ signals, how CF responds to sensory events and contributes to PC dendritic Ca2+ and CS remains unexplored. Here, single or simultaneous Ca2+ imaging of CFs and PCs in awake mice revealed the presynaptic CF Ca2+ amplitude encoded the sensory input's strength and directly influenced post-synaptic PC dendritic Ca2+ amplitude. The sensory-driven variability in CF Ca2+ amplitude depended on the number of spikes in the CF burst. Finally, the spike number of the CF burst determined the PC Ca2+ influx and CS properties. These results reveal the direct translation of sensory information-coding CF inputs into PC Ca2+, suggesting the sophisticated role of CFs as error signals.
Nanoscale assembly is an area of research that has vast implications for molecular design, sensing, nanofabrication, supramolecular chemistry, catalysis, and environmental remediation. Here we show that poly(amidoamine) (PAMAM) dendrimers of both generations 1 (G1) and 4 (G4) can host 1 fullerenol per 2 dendrimer primary amines as evidenced by isothermal titration calorimetry, dynamic light scattering and spectrofluorometry. Thermodynamically, the interactions were similarly spontaneous between both generations of dendrimers and fullerenols, however, G4 formed stronger complexes with fullerenols resulting from their higher surface charge density and more internal voids, as demonstrated by spectrofluorometry. In addition to hydrogen bonding that existed between the dendrimer primary amines and the fullerenol oxygens, hydrophobic and electrostatic interactions also contributed to complex formation and dynamics. Such hybrid of soft and condensed nanoassembly may have implications for environmental remediation of discharged nanomaterials and entail new applications in drug delivery.
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