Conformations of Protonated AlaDap and DapAla Characterized by IRMPD Spectroscopy and Molecular Modeling

Oligopeptides containing 2,3-diaminopropionic acid (Dap) serve as a unique model to study conformational effects on the ionizability of a side-chain group. In this study, conformations of acetylated isomeric dipeptide ions containing alanine (Ala) and Dap, AlaDapH⁺ and DapAlaH⁺, are studied by infrared multiple photon dissociation (IRMPD) spectroscopy and computation. The IRMPD spectra are characterized in detail by comparing them with theoretical IR spectra of a set of low-energy conformations calculated at the ωB97X-D/6-311+G­(d) level of theory. The averaged IR spectra according to the Boltzmann distribution of the set of conformations have a good match to the IRMPD spectra. The characteristic amide I band of AlaDapH⁺ appears to be downshifted compared to that of DapAlaH⁺. The relative positions of the amide band suggest a stronger hydrogen-bonding interaction between the charged side-chain amino group and the amide carbonyl groups in AlaDapH⁺ than in DapAlaH⁺. The stronger hydrogen bonding in the former is likely due to a better alignment of the N–H and OC bonds, which enables an effective sequestering of the positive charge at the amino group. The effect results in a higher proton affinity of acetylated dipeptides with the Dap residue at the C-terminus

Effect of positive coping style on EPDS score as a function of subjective social support.

<p>* “sup.low” means low level of subjective social support. * “sup.mod” means moderate level of subjective social support.</p

Incidence rate of prenatal depression in different studies.

<p>*P<.05 is statistically significant.</p><p>Incidence rate of prenatal depression in different studies.</p

Bivariate correlation analysis of scores in EPDS, social support, and coping styles, and of demographic data.

<p>*Correlation is significant at 0.05 (2-tailed).</p><p>**Correlation is significant at 0.01 (2-tailed).</p><p>P<0.05 is statistically significant.</p><p>Bivariate correlation analysis of scores in EPDS, social support, and coping styles, and of demographic data.</p

Eliminating the Scattering of Thin Film Structures

Rendering invisibility in the wide application scenarios has seen a surge in interest in recent years. Though various approaches have been proposed to realize concealments under different conditions, achieving polarization-independent invisibility for large objects remains a big challenge. Here, we propose to attain invisibility of a large dielectric slab with polarization constraints being totally lifted. This is accomplished by employing an antiscattering coating made of anisotropic metamaterials. We show that by tailoring the electric resonance of a triangular mushroom structure, antiphase electric dipole moment can be induced, resulting in an antipolarization response of the whole metamaterial coatings. By putting the proposed coatings on both sides of a large dielectric slab, a neutralization effect of the total polarization is observed, leading to the peculiar phenomenon of full-polarization invisibility. Our results are validated through full-wave simulations and experimental measurements. Remarkably, the intrinsic null-polarization property of the coating-slab-coating structure guarantees the invisibility feature of a large-scale bulk made by simply stacking the sandwiched composites, which facilitates the application of invisibility in practical scenarios such as the invisibility cloaks and the reflectionless antenna radomes

Supplementary document for Long-term monitoring chlorophyll-a concentration using HJ-1 A/B imagery and machine learning algorithms in typical lakes, a cold semi-arid region - 6943993.pdf

Supplemental Documen