Hicksrice1413

Guanine self-assemblies are promising supramolecular platforms for optoelectronic applications. The study (Hua et al., J. Phys. Chem. C2012, 116, 14,682-14,689) reported that alkaline cations cannot modulate the electronic absorption spectrum of G-quadruplexes, although a cation effect is observable during electronic relaxation due to different mobility of Na+ and K+ cations. In this work, we theoretically examined whether divalent Mg2+ and Ca2+ cations and hydration might shift excited charge-transfer states of a cation-templated stacked G-quartet to the absorption red tail. Our results showed that earth alkaline cations blue-shifted nπ* states and stabilized charge-transfer ππ* states relative to those of complexes with alkaline cations, although the number of charge-separation states was not significantly modified. CP-690550 Earth alkaline cations were not able to considerably increase the amount of charge-transfer states below the Lb excitonic states. Hydration shifted charge-transfer states of the Na+-coordinated G-octet to the absorption red tail, although this part of the spectrum was still dominated by monomer-like excitations. We found G-octet electron detachment states at low excitation energies in aqueous solution. These states were distributed over a broad range of excitation energies and could be responsible for oxidative damage observed upon UV irradiation of biological G-quadruplexes.Structures capable of perfect light absorption promise technological advancements in varied applications, including sensing, optoelectronics, and photocatalysis. While it is possible to realize such structures by placing a monolayer of metal nanostructures above a reflecting surface, there remains limited studies on what effect particle size plays on their capacity to absorb light. Here, we fabricate near-perfect absorbers using colloidal Au nanoparticles, via their electrostatic self-assembly on a TiO2 film supported by a gold mirror. This method enables the control of interparticle spacing, thus minimizing reflection to achieve optimal absorption. Slightly altering the nanoparticle size in these structures reveals significant changes in the spectral separation of hybrid optical modes. We rationalize this observation by interpreting data with a coupled-mode theory that provides a thorough basis for creating functional absorbers using complex colloids and outlines the key considerations for achieving a broadened spectral response.Elastin is the insoluble elastomeric protein that provides extensibility and resilience to vertebrate tissues. Limited high-resolution structural data for elastin are notably complex. To access this information, this protein is considered in the simplified context of its two general domain types, that is, hydrophobic (HP) and crosslinking (CL). The question of elastin's structure-function has directed the focus of nearly all previous studies in the literature to the unique repeating sequences characteristic of this protein, found primarily in the HP domains. The CL domains were assumed to play a very limited role in biological elasticity due in part to the significant α-helical character that was (incorrectly) predicted for these regions. In this study, the conformational heterogeneity of alanines in native elastin's CL domains is examined in the context of helix-coil transition theory (HCTT) using solid-state nuclear magnetic resonance (SSNMR) spectroscopy in tandem with strategic isotopic labeling. Helix and coil populations are observed at all temperatures, but the former increases significantly at lower temperatures. Below the glass transition temperature (Tg), two major populations of alanines in the CL regions are resolved by two-dimensional SSNMR; one-dimensional methods are used for characterization in nativelike conditions. The spectra of 13CO-Ala in the CL regions are simulated using an HCTT-based statistical mechanical representation. Below Tg, longer segments with significant helical probabilities are consistent with the experimental data. At higher temperatures, the SSNMR lineshapes are best fit with a distribution of shorter (Ala) n segments, most in random coil. These results are used to refine a structure-function model for elastin in the context of HCTT, redirecting attention to the CL domains and their role in elasticity.Organophosphate triesters (tri-OPEs) have recently been widely identified in aquatic ecosystems, but information on their organophosphate diester (di-OPE) metabolites is sparsely available. Herein, uniform fishmeal products were collected across the globe (the U.S., China, Europe, South America, and Southeast Asia). Sixteen representative tri-OPEs and eight di-OPEs were investigated to reveal whether industrial production, metabolism, environmental persistence, or physicochemical properties are the key factors influencing their environmental burden and distribution. Tri-OPEs and di-OPEs were 100% detected in fishmeal, with bis(2-chloroethyl) hydrogen phosphate (BCEP) and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) at discernible levels in marine fauna for the first time. Average concentration of di-OPEs (49.6 ± 27.5 ng/g dw) was of the same order of magnitude as that of tri-OPEs (59.3 ± 92.2 ng/g dw). Geographical-specific distributions of tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), triphenyl phosphate (TPhP), tris(2-butoxyethyl) phosphate (TBOEP), and 2-ethylhexyl diphenyl phosphate (EHDPP) were statistically significant (p less then 0.05). Mean concentration ratios ranged from 0.087 for the BCEP-TCEP pair to 507 for the dimethyl phosphate (DMP)-trimethyl phosphate (TMP) pair. Only the TPhP-diphenyl phosphate (DPhP) pair presented a strong positive linear correlation (r = 0.731; p less then 0.01), and DPhP was proved a degradation origin. Commercial sources had a significant overall impact on distribution patterns of the DMP-TMP and the dibutyl phosphate (DnBP) - tri-n-butyl phosphate (TnBP) pairs, whereas biotic transformation and abiotic stability profoundly influenced the bis(2-ethylhexyl) phosphate (BEHP)-tris(2-ethylhexyl) phosphate (TEHP), the bis(1-chloro-2-propyl) phosphate (BCIPP)-TCIPP, and the BCEP-TCEP pairs. Di-OPEs are critical to understand environmental behavior of tri-OPEs in marine fauna.