Circular Dichroism Metamirrors with Near-Perfect Extinction

In nature, the beetle <i>Chrysina gloriosa</i> derives its iridescence by selectively reflecting left-handed circularly polarized light only. Here, an optical analogue is suggested based on an ultrathin metamaterial, which is termed circular dichroism metamirror. A general method to design the circular dichroism metasmirror is presented under the framework of Jones calculus. It is analytically shown that the building block of such a metamirror needs to simultaneously break the <i>n</i>-fold rotational (<i>n</i> > 2) symmetry and mirror symmetry. By combining two layers of anisotropic metamaterial structures, a circular dichroism metamirror is designed in the mid-infrared region, which shows perfect reflectance for left-handed circularly polarized light without reversing its handedness, while it almost completely absorbs right-handed circularly polarized light. These findings offer a new methodology to implement novel photonic devices for a variety of applications, including polarimetric imaging, molecular spectroscopy, and quantum information processing

Promoter Analysis Reveals Globally Differential Regulation of Human Long Non-Coding RNA and Protein-Coding Genes

<div><p>Transcriptional regulation of protein-coding genes is increasingly well-understood on a global scale, yet no comparable information exists for long non-coding RNA (lncRNA) genes, which were recently recognized to be as numerous as protein-coding genes in mammalian genomes. We performed a genome-wide comparative analysis of the promoters of human lncRNA and protein-coding genes, finding global differences in specific genetic and epigenetic features relevant to transcriptional regulation. These two groups of genes are hence subject to separate transcriptional regulatory programs, including distinct transcription factor (TF) proteins that significantly favor lncRNA, rather than coding-gene, promoters. We report a specific signature of promoter-proximal transcriptional regulation of lncRNA genes, including several distinct transcription factor binding sites (TFBS). Experimental DNase I hypersensitive site profiles are consistent with active configurations of these lncRNA TFBS sets in diverse human cell types. TFBS ChIP-seq datasets confirm the binding events that we predicted using computational approaches for a subset of factors. For several TFs known to be directly regulated by lncRNAs, we find that their putative TFBSs are enriched at lncRNA promoters, suggesting that the TFs and the lncRNAs may participate in a bidirectional feedback loop regulatory network. Accordingly, cells may be able to modulate lncRNA expression levels independently of mRNA levels via distinct regulatory pathways. Our results also raise the possibility that, given the historical reliance on protein-coding gene catalogs to define the chromatin states of active promoters, a revision of these chromatin signature profiles to incorporate expressed lncRNA genes is warranted in the future.</p></div

Summary of the results for separation of promoters from protein-coding and lncRNA genes having similar expression pattern in different cell lines.

<p>CGI: CpG Islands, COMBINE: combination of all types of features.</p><p>Summary of the results for separation of promoters from protein-coding and lncRNA genes having similar expression pattern in different cell lines.</p

Performance of the prediction model.

<p>Quality of the models based on the complete feature set and several combinations of features. RE: repetitive elements, PALIN: palindromes, SKEW: A/T and C/G skews, CGI: CpG Islands, TFBS: transcription factor binding sites, WC: word commonality, CS: chromatin states, k-mer: mono-, di-,tri-nucleotide frequencies, COMBINE: combination of all types of features for complete promoter set (CPS).</p

Distribution of histone modification marks in the GM12878 cell line across lncRNA and protein-coding gene promoters.

<p>Figure demonstrates fraction of all promoters covered by chromatin a particular mark. Blue line corresponds to promoters of protein-coding genes; red line corresponds to lncRNA gene promoters. Transparent regions correspond to 5–95% bootstrap confidence interval of the statistics.</p

Solution-Processed DPP-Based Small Molecule that Gives High Photovoltaic Efficiency with Judicious Device Optimization

A solution-processed diketopyrrolopyrrole (DPP)-based small molecule, namely BDT-DPP, with broad absorption and suitable energy levels has been synthesized. The widely used solvents of chloroform (CF) and <i>o</i>-dichlorobenzene (<i>o</i>-DCB) were used as the spin-coating solvent, respectively, and 1,8-diiodooctane (DIO) was used as additive to fabricate efficient photovoltaic devices with BDT-DPP as the donor material and PC71BM as the acceptor material. Devices fabricated from CF exhibit poor fill factor (FF) of 43%, low short-circuit current density (<i>J</i>_sc) of 6.86 mA/cm², and moderate power conversion efficiency (PCE) of 2.4%, due to rapid evaporation of CF, leading to poor morphology of the active layer. When 0.3% DIO was added, the FF and <i>J</i>_sc were improved to 60% and 8.49 mA/cm², respectively, because of the better film morphology. Active layer spin-coated from the high-boiling-point solvent of <i>o</i>-DCB shows better phase separation than that from CF, because of the slow drying nature of <i>o</i>-DCB, offering sufficient time for the self-organization of active-layer. Finally, using <i>o</i>-DCB as the parent solvent and 0.7% DIO as the cosolvent, we obtained optimized devices with continuous interpenetrating network films, affording a <i>J</i>_sc of 11.86 mA/cm², an open-circuit voltage (<i>V</i>_oc) of 0.72 V, an FF of 62%, and a PCE of 5.29%. This PCE is, to the best of our knowledge, the highest efficiency reported to date for devices prepared from the solution-processed DPP-based small molecules

Codeml Results

Codeml Result

DAVID Results By Bin

DAVID Results By Bi

Human ancestry DAVID output

Human ancestry DAVID outpu