Theoretical Exploration on the Magnetic Properties of Ferromagnetic Metallic Glass: An Ising Model on Random Recursive Lattice

The ferromagnetic Ising spins are modeled on a recursive lattice constructed from random-angled rhombus units with stochastic configurations, to study the magnetic properties of the bulk Fe-based metallic glass. The integration of spins on the structural glass model well represents the magnetic moments in the glassy metal. The model is exactly solved by the recursive calculation technique. The magnetization of the amorphous Ising spins, i.e. the glassy metallic magnet is investigated by our modeling and calculation on a theoretical base. The results show that the glassy metallic magnets has a lower Curie temperature, weaker magnetization, and higher entropy comparing to the regular ferromagnet in crystal form. These findings can be understood with the randomness of the amorphous system, and agrees well with others' experimental observations.Comment: 11 pages, 5 figure

Analysis of effects of laryngopharyngeal reflux disease and proton pump inhibitor treatment on Eustachian tube function in patients with obstructive sleep apnea hypopnea

Objective: This study aims to explore the effects of laryngopharyngeal reflux disease (LPRD) and proton pump inhibitor (PPI) treatment on Eustachian tube function in patients with obstructive sleep apnea (OSA). Methods: The Eustachian tube score-7 (ETS-7) was observed before and after PPI treatment in the control group, OSA only group, and OSA + LPRD group. Results: Age, sex, smoking history, and drinking history showed no differences among 3 groups (P &gt; .05). The body mass index (BMI) in the control group was lower than that in other groups (P &lt; .017). Before PPI treatment, the abnormality rate of ETS-7 in the OSA + LPRD group statistically differed from that in the control group and the OSA only group (P &lt; .017). After PPI treatment, the abnormality rate of ETS-7 in the OSA + LPRD group exhibited no significant differences compared with that in the control group and the OSA only group (P &gt; .017), and it declined remarkably compared with that before PPI treatment (75% vs 35%, χ2 = 13.334, P = .001). Moreover, the multivariate analysis revealed that only LPRD had an independent correlation with the abnormality of ETS-7 (OR = 1.245, 95% CI: 1.759–6.861, P = .000). Conclusion: In view of its high incidence in OSA patients, LPRD may be a considerable factor for the high incidence of abnormality rate of ETS-7 in OSA patients, and PPI therapy is of significant value in improving Eustachian tube function in OSA patients with LPRD. </jats:p

Excited-state localization and energy transfer in pyrene core dendrimers with fluorene/carbazole as the dendrons and acetylene as the linkages

A multi-leveled theoretical investigation combining TD-DFT (B3LYP and CAM-B3LYP) methods and a semi-empirical method was conducted to determine the structure-related spectral properties of T-series dendrimers composed of nearly hundreds of atoms, based on a proposed molecular model. Both one-and two-photon absorption spectra of the dendrimer molecules were well reproduced. The "antenna effect" in the dendrimers molecule was theoretically studied. The process of excitation energy localization from chromophores in the branches to the pyrene core before the fluorescence emission was visualized using contours of the charge different density (CDD) between the electronic states. Conclusions based on the theoretical model were drawn about the observed photophysical properties of T-series dendrimers as follows: (a) increasing the generation of a branch would enhance the absorption of photons with a wavelength below 430 nm; (b) enlarging the conjugation of branches would enhance the coupling among the chromophores and would lower the excitation energy; (c) the existence of inter-molecular coupling among the "antenna" chromophores in conjugated branches and the pyrene core would significantly promote two-photon absorption

Spectral and intramolecular charge transfer properties in terminal donor/acceptor-substituted all-trans-α,ω-diphenylpolyenes and α,ω-diphenylpolyynes

The absorption spectra and intramolecular charge transfer (CT) properties of terminal donor/acceptor-substituted all-trans-alpha,omega-diphenylpolyenes (DPE) and alpha,omega-diphenylpolyynes (DPY) molecules with different conjugated bridge length and substitution modes were investigated by using quantum chemical calculations. We calculated the ground state structures and energy of two series of terminal donor/acceptor DPE and DPY by DFT method. The dependence of conjugation length and substitution modes of the electronic absorption spectra was obtained by TDDFT calculation. The hybrid-GGA XC-functional PBE0 employed in this work was selected from several functionals by comparing the calculated electronic spectral data with experimental value. The CIS-based generalized Mulliken-Hush (GMH) approach was further used to calculate coupling values H(AD) of the CT process. The calculation shows that both the HOMO-LUMO energy gaps and average bond length alternations between unsaturated multiple (C C and C = C) and saturated single bonds (C-C) decrease regularly with the extension of conjugation. The effective conjugated length (ECL) of DPE and DPY with the same order MM > MP/PM > PP is found together with the regular red shift of the electronic absorption spectra with the extension of conjugation, resulting from the different pi-electron delocalization and conjugation efficiency. The GMH analysis further suggests that the CT process in both DPE and DPY is predominated by the through-bond mechanism. The remarkable difference of the conjugated length dependence of squared CT coupling between substituted DPE and DPY is the result of the energetic matching degree of the frontier molecular orbitals between donor/acceptor and the conjugated bridge

Trace Solvent as a Predominant Factor To Tune Dipeptide Self-Assembly

Solvent molecules such as water are of key importance for tuning self-assembly in biological systems. However, it remains a great challenge to detect the role of different types of noncovalent interactions between trace solvents and biomolecules such as peptides. In this work, we discover a dominant role of trace amounts of solvents for mediation of dipeptide self-assembly, in which solvent-bridged hydrogen bonding is demonstrated as a crucial force in directing fiber formation. Hydrogen-bond-forming solvents (including ethanol, N,N-dimethylformamide, and acetone) can affect the hydrogen bonding of C=O and N-H in diphenylalanine (FF) molecules with themselves, but this does not induce pi-pi stacking between FF molecules. The directional hydrogen bonding promotes a long-range-ordered arrangement of FF molecules, preferentially along one dimension to form nanofibers or nanobelts. Furthermore, we demonstrate that water with strong hydrogen-bond-forming capability can notably speed up structure formation with long-range order, revealing the importance of water as a trace solvent for regulation of persistent and robust fiber formation.</p

Solvothermally Mediated Self-Assembly of Ultralong Peptide Nanobelts Capable of Optical Waveguiding

The formation of ultralong peptide crystalline nanobelts using a solvothermal approach from a di-phenylalanine gel within 10 min, where the self-assembly process is accelerated by several orders of magnitude compared with the month-long glutaraldehyde induction method previously reported, has been demonstrated. The solvothermal treatment can facilitate the phase separation of di-phenylalanine gels while speeding up the kinetics of the intramolecular cyclization reaction and concomitant crystallization. Moreover, the modulation effect of formaldehyde as an additive is revealed, and that a small amount of formaldehyde leads to thicker crystalline platelets capable of curved optical waveguiding that can potentially be applied in advanced bio-optical and optoelectronic devices, a rare feat with peptide-based crystals