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Photosynthesis, the fundamental process sustaining life on Earth, depends on the photosystem II (PSII) reaction center's ability to initiate the charge transport process. In this study, we have investigated this charge transport process with a focus on the dissimilarity between the two branches of the PSII reaction center, D1 and D2. Utilizing Marcus theory, we have calculated the reorganization energies and activation barriers for all the key steps involved in the charge transport process. Our analysis reveals that while both D1 and D2 branches exhibit similarities in the initial stages, the rate-determining step in the D2 branch has a significantly higher activation barrier (0.2 eV) than D1 branch (0.1 eV), suggesting a much less favorable energetic landscape. Further, the calculation of current-voltage (I-V) characteristics confirms the higher resistance in the D2 branch compared to the D1 branch, emphasizing its nonconductive nature. This comprehensive approach combining energetic and kinetic considerations provides valuable insights into the asymmetry of charge transport in PSII that may be important in optimizing PSII functionality.
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http://dx.doi.org/10.1073/pnas.2405023122 | DOI Listing |
Nature
September 2025
National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, USA.
Controlling spin currents, that is, the flow of spin angular momentum, in small magnetic devices, is the principal objective of spin electronics, a main contender for future energy-efficient information technologies. A pure spin current has never been measured directly because the associated electric stray fields and/or shifts in the non-equilibrium spin-dependent distribution functions are too small for conventional experimental detection methods optimized for charge transport. Here we report that resonant inelastic X-ray scattering (RIXS) can bridge this gap by measuring the spin current carried by magnons-the quanta of the spin wave excitations of the magnetic order-in the presence of temperature gradients across a magnetic insulator.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2025
Gunma University, 1-5-1 Tenjincho, Kiryu, 376-0052, JAPAN.
We review the fabrication and transport characterization of hexagonal boron nitride (hBN)/Bernal bilayer graphene (BLG) moiré superlattices. Due to the moiré effect, the hBN/BLG moiré superlattices exhibit an energy gap at the charge neutrality point (CNP) even in the absence of a perpendicular electric field. In BLG, the application of a perpendicular electric field tunes the energy gap at the CNP, which contrasts with single-layer graphene and is similar to the family of rhombohedral multilayer graphene.
View Article and Find Full Text PDFRedox Biol
September 2025
Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, 14642, USA; Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, 14642, USA. Electronic address:
Mitochondria are central to cellular function, acting as metabolic hubs that regulate energy transduction to communicate cellular status. A key component of this energetic regulation is the mitochondrial membrane potential (MMP), a charge separation across the inner mitochondrial membrane generated by the electron transport chain. Beyond MMP's canonical role in driving ATP synthesis, MMP acts as a dynamic signaling hub.
View Article and Find Full Text PDFJ Colloid Interface Sci
September 2025
State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China. Electronic address:
Polyimide (PI) faces significant challenges in highly integrated and high-frequency electronic devices due to its inherently low thermal conductivity and relatively high dielectric constant (D). In this study, topologically micro-crosslinked PI films were synthesized by incorporating highly conjugated multi-amino polydiacetylene (MAPDA) into a fluorinated PI matrix. The unique alkene-alkyne alternating conjugated structure of MAPDA, combined with the strong electron-withdrawing trifluoromethyl groups in the matrix, promotes charge redistribution and reduces the dipole moment and polarizability.
View Article and Find Full Text PDFJ Colloid Interface Sci
September 2025
College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China. Electronic address:
Moisture-driven energy generators (MEGs) represent a renewable energy technology, yet challenges such as environmental humidity dependence and transient power generation behavior hinder their practical applications. Herein, a high-performance bilayer MEG is developed by integrating MXene-impregnated paper with a polyacrylamide (PAM) hydrogel to realize environmental tolerance and sustained power generation. Electronegative MXene and paper with 3D porous structure synergistically facilitate selective transport of positive charge, while the hydrogel serves as a water reservoir to provide a moist environment and migratory ions.
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