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To elucidate the energy transfer mechanism of the PE545 light-harvesting complex, an exciton model is constructed with the full Hamiltonian obtained from structure-based calculations. The electronic couplings and spectral densities are evaluated on the basis of the site energies and transition dipole moments obtained from our recent Molecular Dynamics–Quantum Mechanical/Molecular Mechanical (MD–QM/MM) study [Tong et al., J. Phys. Chem. B 123, 2040–2049 (2019)]. The polarized protein-specific charge model is employed both in the MD simulation and in the QM/MM calculations to account for the environmental fluctuation of the protein scaffold. The energy transfer pathways are, thus, derived, which agree well with the phenomenological models based on the spatial organization of the chromophores and the experimental observations. Moreover, the simulated linear absorption spectra using the dissipaton equation of motion approach agree well with the experimental ones, and the resulting population dynamics indicates that an optimal energy transfer efficiency is reproduced. [ABSTRACT FROM AUTHOR]

The fabrication is described of self-assembled In0.9(Ga/Al)0.1As quantum dots in an InAlAs matrix and characterizations are performed using transmission electron microscopy.

Computational prediction of the pKa of ionizable groups remains a central challenge in biomolecular modeling. Although all-atom fixed-charge force fields could be accurate to describe the interaction network within the biomolecules, proper sampling techniques are required to obtain the thermodynamic information in the (de)protonation event. Sufficient sampling requires an ensemble of structures from simulations with proper treatments of the acid-base equilibria, and the grand canonical simulation technique could be used to model the growth/annihilation of hydrogen atoms by merging Hamiltonians of different protonation states into one simulation ensemble. The electrostatic feature of nucleotide systems is especially difficult to model, and the situation becomes more challenging when the ionizable site is highly perturbed. Although there are many successful predictions obtained from the grand canonical constant pH simulations, few reports focus on highly perturbed nucleotide systems with unconventional base-pair features. In this work, with the discrete constant pH method, we investigate the titration thermodynamics of an adenine in the catalytic triad in a 35-nucleotide single-stranded RNA hairpin, featuring an unconventional GA mismatch and a substantially shifted pKa value. Validation tests are performed with two system setups, both of which provide pKa predictions in good agreement with the experimental value. A single-configuration-based technique is used to calculate the pKa for comparison. The current success indicates the predictive power of the current nucleotide modeling framework. • The high pKa shift in the unconventional GA mismatch in a 35-nucleotide single-stranded RNA hairpin is calculated with grand canonical simulations. • The single-configuration-based pKa prediction method named DelPhiPKa cannot reproduce the significant pKa shift. • Our constant pH simulations with two system setups consistently provide predictions in agreement with the experimental reference. [ABSTRACT FROM AUTHOR]

Background: Microelectrode recording (MER) for target refinement is widely used in deep brain stimulator insertion for Parkinson disease. Signals may be influenced by anesthetics when patients receive general anesthesia (GA). This study determined the inhibitory concentration (IC) of propofol on MER signals when it was coadministered with dexmedetomidine. Methods: Patients were anesthetized with dexmedetomidine (0.5 μg·kg-1 loading, followed by infusion at 0.4 μg·kg-1h-1) and propofol through target-controlled infusion for GA with tracheal intubation. The surgeon conducted the online scoring of the background signals, spiking frequency, amplitude, and pattern of single-unit activities by using a 0-10 verbal numerical rating scale (NRS; 0, maximal suppression; 10, minimal suppression), and responses were grouped into suppression (NRS ≤ 6) and nonsuppression (NRS > 6). The median inhibitory concentration (IC50) of propofol (as target effect-site concentrations: Ceprop) was determined using modified Dixon's up-and-down method. Probit regression analysis was further used to obtain the dose--response relationship, and IC05 and IC95 were calculated. Results: Twenty-three adult patients participated in this study. Under the concomitant infusion of dexmedetomidine, the predicted IC50 value (95% CI) of Ceprop for neuronal suppression during MER was 1.29 (1.24-1.34) μg·mL-1 as calculated using modified Dixon's up-and-down method. Using probit analysis, the estimated IC05, IC50, and IC95 values (95% CIs) were 1.17 (0.87-1.23), 1.28 (1.21-1.34), and 1.40 (1.33-1.85) μg·mL-1, respectively. Conclusion: Our data provided reference values of propofol for dosage adjustment to avoid interference on MER under GA when anesthetics have to be continuously infused during recording. [ABSTRACT FROM AUTHOR]

Zn0.95-xCo0.05LixO (x=0–0.12) thin films were synthesized by sol-gel method. Magnetic investigation showed that the ferromagnetism of the Zn0.95-xCo0.05LixO films increased with Li doping within the solubility limit of 9% but dropped sharply when x>9% owing to the presence of the second-phase LiCoO2. X-ray diffraction, UV-visible absorption spectrum (UV-vis), Raman spectrum (Raman), and electrical resistivity investigation indicated that the Li-doping process in Zn0.95Co0.05O was of three stages. The structure and magnetic properties of Zn0.95-xCo0.05LixO films had different change trends in different stages. It was found that not only LiZn′ related defects but also Li+ interstitials played important roles in enhancing the magnetic interaction between Co2+ ions, which was supported by the bound magnetic polaron model. [ABSTRACT FROM AUTHOR]

The Zn1-xCoxO (x=0–0.20) nanocrystals synthesized via sol-gel method have been systematically investigated by using x-ray diffraction, transmission electronic microscopy (TEM), Raman spectrometer (Raman), UV-vis spectrometer (UV-vis), and vibrating sample magnetometer. It is found that the crystal lattice constant (a) and the cell volume of Zn1-xCoxO are irrespective of the Co composition x when x<0.05, while it expands gradually as x increasing from 0.05 to 0.2. This result is different from the existent reports, which indicated the lattice constant (a) and the cell volume both increase consecutively with Co-doping. Detailed Raman, UV-vis, and TEM study suggest the expansion of lattice constant when x>0.05 is attributed to the formation of the Co3O4 phase in Zn1-xCoxO due to the self-purification mechanism in nanocrystals growth process. The formation of the antiferromagnetic Co3O4 well explains the decrease in Zn1-xCoxO ferromagnetism with the increase in Co-doping when x>0.05. [ABSTRACT FROM AUTHOR]

Sol-gel method is used for preparing [Zn.sub.0.95-x][Co.sub.0.05][Li.sub.x]O thin films and magnetic examination has shown that the ferromagnetism of these films can be increased with Li doping. The studies have shown that not only LiZn related defects but also [Li.sup.+] interstitials have played major roles in increasing the magnetic interaction between [Co.sup.2+] ions, which is supported by the bound magnetic polaron model.

The [Zn.sub.1-x][Co.sub.x]O nanocrystals prepared via sol-gel method are examined by using x-ray diffraction, transmission electronic microscopy (TEM), Raman spectrometer (Raman), UV-vis spectrometer (UV-vis) and vibrating sample magnetometer. The formation of the antiferromagnetic [Co.sub.3][O.sub.4] well has described the decrease in [Zn.sub.1-x][Co.sub.x]O ferromagnetism with the increase in Co-doping.