ZnS-Sb₂S₃@C Core-Double Shell Polyhedron Structure Derived from Metal–Organic Framework as Anodes for High Performance Sodium Ion Batteries

Taking advantage of zeolitic imidazolate framework (ZIF-8), ZnS-Sb₂S₃@C core-double shell polyhedron structure is synthesized through a sulfurization reaction between Zn²⁺ dissociated from ZIF-8 and S^2– from thioacetamide (TAA), and subsequently a metal cation exchange process between Zn²⁺ and Sb³⁺, in which carbon layer is introduced from polymeric resorcinol-formaldehyde to prevent the collapse of the polyhedron. The polyhedron composite with a ZnS inner-core and Sb₂S₃/C double-shell as anode for sodium ion batteries (SIBs) shows us a significantly improved electrochemical performance with stable cycle stability, high Coulombic efficiency and specific capacity. Peculiarly, introducing a carbon shell not only acts as an important protective layer to form a rigid construction and accommodate the volume changes, but also improves the electronic conductivity to optimize the stable cycle performance and the excellent rate property. The architecture composed of ZnS inner core and a complex Sb₂S₃/C shell not only facilitates the facile electrolyte infiltration to reduce the Na-ion diffusion length to improve the electrochemical reaction kinetics, but also prevents the structure pulverization caused by Na-ion insertion/extraction. This approach to prepare metal sulfides based on MOFs can be further extended to design other nanostructured systems for high performance energy storage devices

Preparation of 5′-O-(1-Thiotriphosphate)-Modified Oligonucleotides Using Polymerase-Endonuclease Amplification Reaction (PEAR)

<div><p>Antisense oligonucleotides (ASODNs) have been widely used as an important tool for regulating gene expression, and developed into therapeutics. Natural ODNs are susceptible to nuclease degradation, nucleic acid analogues, however, have less side effects, stronger stability and more potent activities. Large-scale <i>de novo</i> synthesis of a certain oligonucleotide has been very difficult and costly. In a previous preliminary study, we developed the polymerase-endonuclease amplification reaction (PEAR) for amplification and large-scale preparation of natural antisense ODNs. Here we extended the method in preparation of a widely used modified oligonucleotide with 5′-O-(1-Thiotriphosphate) modifications. Using electrospray ionization liquid chromatography mass spectrometry (ESI/LC/MS) detection, the purity of the PEAR product was measured as high as 100.0%. Using PEAR a large amount of a specific oligonucleotide can be produced starting from a small amount of synthetic seeds. It is suggested that PEAR can be a useful tool for large-scale production of modified oligonucleotides.</p></div

The LC/UV Chromatogram and Deconvoluted Mass Spectrum of the *A*G PEAR product.

<p>Components: (A) RT = 7.45 min: MW = 6742.0; (B) RT = 8.00 min; (C) RT = 8.38 min; (D) RT = 8.76 min; (E) RT = 9.05 min; See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0067558#pone.0067558.s001" target="_blank">Table S2 in File S1</a> for detailed characterization of components.</p

Molecular structure representation of dNTPαSs.

<p>Molecular structure representation of dNTPαSs.</p

MicroRNAs activate gene transcription epigenetically as an enhancer trigger

<p>MicroRNAs (miRNAs) are small non-coding RNAs that function as negative gene expression regulators. Emerging evidence shows that, except for function in the cytoplasm, miRNAs are also present in the nucleus. However, the functional significance of nuclear miRNAs remains largely undetermined. By screening miRNA database, we have identified a subset of miRNA that functions as enhancer regulators. Here, we found a set of miRNAs show gene-activation function. We focused on miR-24-1 and found that this miRNA unconventionally activates gene transcription by targeting enhancers. Consistently, the activation was completely abolished when the enhancer sequence was deleted by TALEN. Furthermore, we found that miR-24-1 activates enhancer RNA (eRNA) expression, alters histone modification, and increases the enrichment of p300 and RNA Pol II at the enhancer locus. Our results demonstrate a novel mechanism of miRNA as an enhancer trigger.</p