The free energy of pore formation in lipid bilayers has been previously calculated using a variety of reaction coordinates. Here, we use free energy perturbation of a cylindrical lipid exclusion restraint to compute the free energy profile as a function of pore radius in dimyristoylphosphatidylcholine (DMPC) and dioleoylphosphatidylcholine (DOPC) bilayers. Additionally restraining the headgroups to lie on the membrane surface allows us to also calculate the free energy profile of hydrophobic pores, i.e., cylindrical pores lined by acyl chains. For certain pore radii, the free energy of wetting of hydrophobic pores is calculated using the density bias method. It is found that wetting of hydrophobic pores becomes thermodynamically favorable at 5.0 Å for DMPC and 6.5 Å for DOPC, although significant barriers prevent spontaneous wetting of the latter on a nanosecond time scale. The free energy of transformation of hydrophilic pores to hydrophobic ones is also calculated using free energy perturbation of headgroup restraints along the bilayer normal. This quantity, along with wetting and pore growth free energies, provides complete free energy profiles as a function of radius. Pore line tension values for the hydrophilic pores obtained from the slope of the free energy profiles are 37.6 pN for DMPC and 53.7 pN for DOPC. The free energy profiles for the hydrophobic pores are analyzed in terms of elementary interfacial tensions. It is found that a positive three-phase line tension is required to explain the results. The estimated value for this three-phase line tension (51.2 pN) lies within the expected range.
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http://dx.doi.org/10.1063/5.0016682 | DOI Listing |
Langmuir
January 2025
Department of Chemistry, Faculty of Science, University of Kurdistan, Pasdaran Boulevard, Sanandaj 66177-15175, Iran.
Water splitting by an electrochemical method to generate hydrogen gas is an economic and green approach to resolve the looming energy and environmental crisis. Designing a composite electrocatalyst having integrated multichannel charge separation, robust stability, and low-cost facile scalability could be considered to address the issue of electrochemical hydrogen evolution. Herein, we report a superhydrophilic, noble-metal-free bimetallic nanostructure TiO/NiP coated on graphitic polyacrylonitrile carbon fibers (g-C/TiO/NiP) using a facile hydrothermal method followed by phosphorylation.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry, Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, Beihang University, Beijing 100191, China.
Potassium (K)-based batteries hold great promise for cryogenic applications owing to the small Stokes radius and weak Lewis acidity of K. Nevertheless, energy-dense (>200 W h kg) K batteries under subzero conditions have seldom been reported. Here, an over 400 W h kg K battery is realized at -40 °C via an anode-free and dual-ion strategy, surpassing these state-of-the-art K batteries and even most Li/Na batteries at low temperatures (LTs).
View Article and Find Full Text PDFNeural Comput
January 2025
Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, 200437, China
Spiking neural networks (SNNs) have attracted significant interest in the development of brain-inspired computing systems due to their energy efficiency and similarities to biological information processing. In contrast to continuous-valued artificial neural networks, which produce results in a single step, SNNs require multiple steps during inference to achieve a desired accuracy level, resulting in a burden in real-time response and energy efficiency. Inspired by the tradeoff between speed and accuracy in human and animal decision-making processes, which exhibit correlations among reaction times, task complexity, and decision confidence, an inquiry emerges regarding how an SNN model can benefit by implementing these attributes.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.
ConspectusPhotochemical reactions have always been the source of a great deal of mystery. While classified as a type of chemical reaction, no doubts are allowed that the general tenets of ground-state chemistry do not directly apply to photochemical reactions. For a typical chemical reaction, understanding the critical points of the ground-state potential (free) energy surface and embedding them in a thermodynamics framework is often enough to infer reaction yields or characteristic time scales.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Inner Mongolia Key Laboratory of Advanced Ceramic Materials and Devices, School of Materials Science and Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China.
Lead-free ceramic-based dielectric capacitors are critical in electronics and environmental safety. Nevertheless, developing ideal lead-free ceramics with excellent energy storage properties remains a challenging task for practical applications. Herein, the enhanced relaxation behavior and increased breakdown electric field are utilized to realize the high energy storage behavior of (0.
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