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Our calculations found that the O thereforeO three-electron (3e) bonds (2.16 approximately 2.27 A) can be formed not only between two neighboring peptide units in a main chain but also between two adjacent peptide units in two different main chains in proteins. This finding may address electron hole migration from one peptide unit to the next in proteins. Evidently, stability of the O thereforeO 3e bonded species is strongly dependent on the component of the oligopeptides and is reduced owing to the steric hindrance of the side chains when the big chains present in oligopeptides. Besides, formation of the O thereforeO 3e bonds competes with the formation of the other forms of three-electron bonds depending on the component of the polypeptides. Formation of the O thereforeS 3e bond is thermodynamically more favorable than that of the O thereforeO 3e bond for the oligopeptides containing sulfur atom in their side chains. Similarly, formation of the O thereforepi 3e bond between aromatic ring of the side chain and the neighboring peptide unit is more stable than that of the O thereforeO 3e bond when the aromatic amino acids present in the oligopeptides. We infer that a series of three-electron bonds may be formed during the electron hole migration along the peptide backbone in proteins and assist electron hole transport as relay stations, supporting the peptide chain as a conduction wire. The ab initio molecular dynamics simulations of the polypeptides also support this conclusion.

We present the first approach to the excess electron solvation in a novel medium, room-temperature ionic liquid, using ab initio molecular dynamics simulation techniques in this work. Results indicate that an excess electron can be solvated in the [dmim] + Cl -IL as long-lived delocalized states and two short-lifetime localized states, one a single-cation-residence parasitical type and the other a double-cation-based solvated type state. The presence of a low-lying π*-LUMO as the site of excess electron residence in the cation moiety disables the C-H unit as a H-bond donor, while the aromaticity requirement of the rings and the effect of the counterion Cl -'s make the resulting ion pairs a weak stabilizer for an excess electron. Although no large solvent reorganization in IL was found at the picosecond scale, the IL fluctuations sufficiently modify the relative energy levels of the excess electron states to permit facile state-to-state conversion and adiabatic migration. The binding energy of the excess electron is only ∼0.2 eV, further indicating that it is in a quasi-free state, with a large drift mobility, suggesting that ILs are unreactive and promising mediators for transport of excess electrons, in agreement with the experimental findings. The present study provides insight into the novel electron solvation character in a new class of promising media for physical and chemical processes, which are fundamental for understanding of electron migration mechanisms in IL-based applications.The nature of an excess electron (EE) in various media has been extensively explored because of its fundamental importance in Chemistry and Physics and its relevance to a large class of physical and chemical phenomena associated with charge migration, radical reactions, and polarons. 1,2 Although the EE has been shown to exist in either solvated and/or surface states in some molecular solvents 2-6 and in a localized F-center-like state in alkali halide molten salts, 7,8 its properties and transport mechanisms in other media remain poorly understood. In particular, recently developed room-temperature ionic liquids (IL) appear to be promising "green" media and have found many intriguing applications in synthetic chemistry, separation science, materials, and electrochemical devices such as batteries and solar cells. 9 However, the states and evolution dynamics of migrating electrons in IL are still relatively unexplored.IL are also an interesting topic for basic science, and their characteristic properties are being investigated with various techniques. 10 ILs are a special ionic "molten salt" characterized as a liquid at or near room temperature, and they may have novel solvation properties. Their ionic nature implies that they might be able to affect efficient charge separation and to modulate charge migration via a solvent-mediated pathway, as demonstrated by a few recent experimental studies. 10 They are, therefore, much different from conventional polar molecular solvents, with favorable stabilization and transport roles for ...

The extensive application of nanomaterials in industry, medicine and consumer products has raised concerns about their potential toxicity. The female population is particularly vulnerable and deserves special attention because toxicity in this group may impact both female reproductivity and fetal development. Mouse and zebrafish models each have their own unique features and studies using these models to examine the potential toxicity of various nanoparticles are compared and summarized in this review. Several nanoparticles exhibit detrimental effects on female reproductivity as well as fetal development, and these adverse effects are related to nanoparticle composition, surface modification, dose, exposure route and animal species. Limited studies on the mechanisms of nanotoxicity are also documented and reviewed herein.

The structural and electronic properties of an excess electron (EE) in the ionic liquid (IL) 1-methylpyridinium chloride were explored using ab initio molecular dynamics simulations and quantum chemical calculations to give an overall understanding of the solvation and transport behavior of an EE in this IL. The results show that the EE resides in cation pi*-type orbitals and that the electronic states can be characterized by the alternating appearance of localized and delocalized states during the time evolution. The characters of the EE electronic states are determined by the number of cations contributing to the LUMO of the IL. In a localized state one or two cations contribute to the LUMO of the bulk ionic liquid, while in the delocalized state the IL LUMO is composed of pi*-type orbitals spanning nearly all the cations in the cell. The arrangement and fluctuation-induced changes of the orbital components in the empty band produce an alternation of different states and leads to the migration of the excess electron. These findings can be attributed to the special features of the electronic structures and geometries of the IL, and they can be used to explain similarities and differences between pyridinium-based and imidazolium-based ILs in mediating electron migration.

This meta-analysis suggested that maternal passive smoking during pregnancy was associated with an increased risk of total NTDs and three NTDs subtypes in offspring. Specifically, the associations were also found to be significantly positive both in China and USA.

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Women who smoked during pregnancy had mildly elevated risk of having infants with NTDs.