Photochemically Reversible and Thermally Stable Axially Chiral Diarylethene Switches

A series of dithienylcyclopentenes containing axially chiral 1,1′-binaphthyl units were successfully synthesized by a Suzuki–Miyaura protocol. All these compounds exhibited photochemically reversible isomerization with thermal stability in both organic solvent and a liquid crystal (LC) host. When doping into an achiral LC host, some of them exhibited very high helical twisting powers. Reversible reflection wavelength tuning in the visible region and LC phase switching between nematic and cholesteric upon light irradiation were demonstrated

Enhanced Electrochemical Performance of Three-Dimensional Ni/Si Nanocable Arrays as a Li-Ion Battery Anode by Nitrogen Doping in the Si Shell

In the present study, a configuration of three-dimensional Ni core/sputtered Si shell nanocable arrays is proposed to alleviate the severe volumetric change of Si during lithiation/delithiation. In particular, the effects of N doping in the Si shell on the electrochemical performance of the nanocable array electrodes have been investigated. It has been found that reduced interfacial resistance, enhanced effective Li ion diffusion coefficient in the active material, and more stable surface passivating layer are likely to be achieved by N doping, leading to an improvement of the rate performance and cyclability when compared to the undoped nanocable array counterpart

A↔G and C↔T fourfold degenerate site sSNPs.

a<p>χ² test of the difference of substitution direction between the first 50 codons and the remainder codons; * <i>P</i><0.05; **<i>P</i><0.01.</p><p>Significant distribution bias of sSNPs between the 3^rd ∼50^th codons and the 51^st ∼ remainder codons was identified at non-CpG sites.</p

Human Coding Synonymous Single Nucleotide Polymorphisms at Ramp Regions of mRNA Translation

<div><p>According to the ramp model of mRNA translation, the first 50 codons favor rare codons and have slower speed of translation. This study aims to detect translational selection on coding synonymous single nucleotide polymorphisms (sSNP) to support the ramp theory. We investigated fourfold degenerate site (FFDS) sSNPs with A↔G or C↔T substitutions in human genome for distribution bias of synonymous codons (SC), grouped by CpG or non-CpG sites. Distribution bias of sSNPs between the 3^rd ∼50^th codons and the 51^st ∼ remainder codons at non-CpG sites were observed. In the 3^rd ∼50^th codons, G→A sSNPs at non-CpG sites are favored than A→G sSNPs [<i>P</i> = 2.89×10⁻³], and C→T at non-CpG sites are favored than T→C sSNPs [<i>P</i> = 8.50×10⁻³]. The favored direction of SC usage change is from more frequent SCs to less frequent SCs. The distribution bias is more obvious in synonymous substitutions CG(G→A), AC(C→T), and CT(C→T). The distribution bias of sSNPs in human genome, i.e. frequent SCs to less frequent SCs is favored in the 3^rd ∼50^th codons, indicates translational selection on sSNPs in the ramp regions of mRNA templates.</p> </div

The distribution bias of (C→T) and (T→C) at non-CpG sites of the ramp regions.

<p>(a) The ratio of AC(C→T)/AC(T→C) at non-CpG sites of the ramp regions is larger than that at the reminder coding regions(<i>P</i> = 0.006). (b) The ratio of CT(C→T)/CT(T→C) at non-CpG sites of the ramp regions is larger than that at the reminder coding regions (<i>P</i> = 0.029).</p

A↔G fourfold degenerate site sSNPs.

a<p>χ² test of the difference of substitution direction between the first 50 codons and the remainder codons; *Uncorrected <i>P</i><0.05. By Bonferroni correction for multiple comparisons, the threshold for statistical significance is <i>P</i><0.00625.</p><p>The G→A bias was mainly explained by the CG(G→A) substitution at non-CpG sites.</p

The distribution bias of CG(G→A) and CG(A→G) at the ramp regions.

<p>The ratio of CG(G→A)/CG(A→G) at the ramp regions is larger than that at the reminder coding regions (<i>P</i> = 0.040). CG(A↔G) synonymous substitutions are all at non-CpG sites.</p

Reversible Light-Directed Red, Green, and Blue Reflection with Thermal Stability Enabled by a Self-Organized Helical Superstructure

Adding external, remote, and dynamic control to self-organized superstructures with desired properties is an important leap necessary in leveraging the fascinating molecular subsystems for employment in applications. Here two novel light-driven dithienylethene chiral molecular switches possessing remarkable changes in helical twisting power during photoisomerization as well as very high helical twisting powers were found to experience photochemically reversible isomerization with thermal stability in both isotropic organic solvents and anisotropic liquid crystal media. When doped into a commercially available achiral liquid crystal host, the chiral switch was able to either immediately induce an optically tunable helical superstructure or retain an achiral photoresponsive liquid crystal phase whose helical superstructure was induced and tuned reversibly upon light irradiation. Moreover, reversible light-directed red, green, and blue reflection colors with thermal stability in a single thin film were demonstrated

Free Energy Calculation of Nanodiamond-Membrane AssociationThe Effect of Shape and Surface Functionalization

Nanodiamonds (NDs) are nanoscale diamond particles with broad applications in biosensing, drug delivery, and long-term tracking. Their interactions with a membrane dictate both the endocytosis process and subsequent intracellular fate of the nanoparticles. However, details of ND-membrane association and the energetics of this process remain largely unknown. In this work, we use all-atom molecular dynamics (MD) simulations to determine the free energy profile and molecular details of ND-membrane association, with a focus on the impact of shape and surface functionalization. Through altogether 6.5 μs umbrella sampling on six atomistic ND models of different shapes (spherical or pyramidal) and surface functionalization (5%, 35%, and 55%), we show that nanodiamonds associate favorably with the membrane, which is largely driven by ND–lipid interactions. During its membrane association, the shape of a nanodiamond plays a key role in determining the location of the free energy minimum, while its surface functionalization modulates the depth of the minimum. Of the six models studied here, all spherical NDs adhere to the bilayer surface, whereas pyramidal NDs, with the exception of the most functionalized P55, anchor inside the membrane. Shape also dominates the height of the free energy barrier: the sharp pyramidal NDs have much lower barriers against penetrating a POPC bilayer than spherical ones. Our all-atom ND models and their bilayer association strength determined here can be combined with future coarse-grained or continuum models to further explore ND–membrane interactions on larger length scales

Controllable Self-Assembling of Gold Nanorods via On and Off Supramolecular Noncovalent Interactions

5,15-Bis­(4-sulfonatophenyl)­porphyrin (<b>DPPS</b>) with a planar conjugated system and two negative charges was found to be able to engender the self-assembling of CTAB-<b>GNR</b>s due to the electrostatic interaction between <b>DPPS</b> and CTAB together with the π–π intermolecular interaction of <b>DPPS</b>, while its bulky supramolecular pseudo[3]­rotaxane included by β-cyclodextrin prevented such self-assembling due to the interruption of the above noncovalent interactions