Overexpressing NeuroD1 reprograms Müller cells into various types of retinal neurons.

The onset of retinal degenerative disease is often associated with neuronal loss. Therefore, how to regenerate new neurons to restore vision is an important issue. NeuroD1 is a neural transcription factor with the ability to reprogram brain astrocytes into neurons in vivo. Here, we demonstrate that in adult mice, NeuroD1 can reprogram Müller cells, the principal glial cell type in the retina, to become retinal neurons. Most strikingly, ectopic expression of NeuroD1 using two different viral vectors converted Müller cells into different cell types. Specifically, AAV7m8 GFAP681::GFP-ND1 converted Müller cells into inner retinal neurons, including amacrine cells and ganglion cells. In contrast, AAV9 GFAP104::ND1-GFP converted Müller cells into outer retinal neurons such as photoreceptors and horizontal cells, with higher conversion efficiency. Furthermore, we demonstrate that Müller cell conversion induced by AAV9 GFAP104::ND1-GFP displayed clear dose- and time-dependence. These results indicate that Müller cells in adult mice are highly plastic and can be reprogrammed into various subtypes of retinal neurons.

Leaky Mode Resonance-Induced Sensitive Ultraviolet Photodetector Composed of Graphene/Small Diameter Silicon Nanowire Array Heterojunctions.

Ultraviolet photodetectors (UVPDs) based on wide band gap semiconductors (WBSs) are important for various civil and military applications. However, the relatively harsh preparation conditions and the high cost are unfavorable for commercialization. In this work, we proposed a non-WBS UVPD by using a silicon nanowire (SiNW) array with a diameter of 45 nm as building blocks. Device analysis revealed that the small diameter SiNW array covered with monolayer graphene was sensitive to UV light but insensitive to both visible and infrared light illumination, with a typical rejection ratio of 25. Specifically, the responsivity, specific detectivity, and external quantum efficiency under 365 nm illumination were estimated to be 0.151 A/W, 1.37 × 1012 Jones, and 62%, respectively, which are comparable to or even better than other WBS UVPDs. Such an abnormal photoelectrical characteristic is related to the HE1m leaky mode resonance (LMR), which is able to shift the peak absorption spectrum from near-infrared to UV regions. It is also revealed that this LMR is highly dependent on the diameter and the period of the SiNW array. These results show narrow band gap semiconductor nanostructures as promising building blocks for the assembly of sensitive UV photodetectors, which are very important for various optoelectronic devices and systems.

Direct Synthesis of Polyurea Thermoplastics from CO2 and Diamines.

The transformation of CO2 into polymeric materials is an important and hot research topic from the viewpoint of renewable resources and environmental effects. Herein, a series of polyureas have been synthesized by polycondensation from CO2 with diamines of 1,12-diaminododecane (DAD) and/or 4,7,10-trioxa-1,13-tridecanediamine (TTD). The properties of polyureas synthesized were characterized by FTIR, 1H NMR, 13C NMR, XRD, DSC, TGA, and DMA. The polyureas synthesized from CO2 with a mixture of diamines presented high performances compared to those of polyureas synthesized from CO2 with a single diamine. The thermal and mechanical properties were improved largely by the variation in the crystallization and the chain flexibility depending on the changes in the density and/or intensity of hydrogen bonds. With increasing amounts of TTD from 0 to 100% in weight, the melting (Tm), crystallization (Tc), and glass transition (Tg) temperatures decreased from 207 to 116 °C, from 181 to 54 °C, and from 66 to -34 °C, respectively. When the TTD content was increased from 0 to 50 wt %, the Young's modulus decreased from 1170 to 406 MPa, and the tensile strength decreased from 53.3 to 42.9 MPa. However, the elongation at break increased from 13 to 330%. Furthermore, the chain length of aliphatic diamines and polyetheramines had a significant effect on the mechanical properties. The initial decomposition temperature (Td,5%) is >295 °C, about 110 °C higher than the Tm (116-207 °C), which is advantageous for the postprocessing. The mechanical properties of the polyureas synthesized herein are superior to those of polycarbonate and polyamide 6. Thus, polyureas synthesized from the renewable and cheap resources, CO2 and diamines, will find wide potential applications in the field of polymeric materials.

Genomic profiling of exogenous abscisic acid-responsive microRNAs in tomato (Solanum lycopersicum).

BACKGROUND: Plant microRNAs (miRNAs) are involved in various biological pathways and stress responses as negative regulators at the posttranscriptional level. Abscisic acid (ABA) is a key signaling molecule that mediates plant stress response by activating many stress-related genes. Although some miRNAs in plants are previously identified to respond to ABA, a comprehensive profile of ABA-responsive miRNAs has not yet been elucidated. RESULTS: Here, we identified miRNAs responding to exogenous application of ABA, and their predicted target genes in the model plant organism tomato (Solanum lycopersicum). Deep sequencing of small RNAs from ABA-treated and untreated tomatoes revealed that miRNAs can be up- or down-regulated upon treatment with ABA. A total of 1067 miRNAs were detected (including 365 known and 702 candidate novel miRNAs), of those, 416 miRNAs which had an abundance over two TPM (transcripts per million) were selected for differential expression analysis. We identified 269 (180 known and 89 novel) miRNAs that respond to exogenous ABA treatment with a change in expression level of |log2FC|≥0.25. 136 of these miRNAs (90 known and 46 novel) were expressed at significantly different levels |log2FC|≥1 between treatments. Furthermore, stem-loop RT-PCR was applied to validate the RNA-seq data. Target prediction and analysis of the corresponding ABA-responsive transcriptome data uncovered that differentially expressed miRNAs are involved in condition stress and pathogen resistance, growth and development. Among them, approximately 90 miRNAs were predicted to target transcription factors and pathogen resistance genes. Some miRNAs had functional overlap in biotic and abiotic stress. Most of these miRNAs were down-regulated following exposure to exogenous ABA, while their related target genes were inversely up-regulated, which is consistent with their negative regulatory role in gene expression. CONCLUSIONS: Exogenous ABA application influences the composition and expression level of tomato miRNAs. ABA mainly down-regulates miRNAs that their target genes involve in abiotic stress adaption and disease resistance. ABA might increase expression of stress-related genes via miRNA-mediated posttranscriptional regulation, and our results indicate that ABA treatment has the potential to improve both abiotic stress tolerance and pathogen resistance. This study presents a comprehensive profile of ABA-regulated miRNAs in the tomato, and provides a robust database for further investigation of ABA regulatory mechanisms.

Heat Shock Factor Genes of Tall Fescue and Perennial Ryegrass in Response to Temperature Stress by RNA-Seq Analysis.

Heat shock factors (Hsfs) are important regulators of stress-response in plants. However, our understanding of Hsf genes and their responses to temperature stresses in two Pooideae cool-season grasses, Festuca arundinacea, and Lolium perenne, is limited. Here we conducted comparative transcriptome analyses of plant leaves exposed to heat or cold stress for 10 h. Approximately, 30% and 25% of the genes expressed in the two species showed significant changes under heat and cold stress, respectively, including subsets of Hsfs and their target genes. We uncovered 74 Hsfs in F. arundinacea and 52 Hsfs in L. perenne, and categorized these genes into three subfamilies, HsfA, HsfB, and HsfC based on protein sequence homology to known Hsf members in model organisms. The Hsfs showed a strong response to heat and/or cold stress. The expression of HsfAs was elevated under heat stress, especially in class HsfA2, which exhibited the most dramatic responses. HsfBs were upregulated by the both temperature conditions, and HsfCs mainly showed an increase in expression under cold stress. The target genes of Hsfs, such as heat shock protein (HSP), ascorbate peroxidase (APX), inositol-3-phosphate synthase (IPS), and galactinol synthase (GOLS1), showed strong and unique responses to different stressors. We comprehensively detected Hsfs and their target genes in F. arundinacea and L. perenne, providing a foundation for future gene function studies and genetic engineering to improve stress tolerance in grasses and other crops.

Connected-sea partons.

According to the path-integral formalism of the hadronic tensor, the nucleon sea contains two distinct components called the connected sea (CS) and the disconnected sea (DS). We discuss how the CS and DS are accessed in the lattice QCD calculation of the moments of the parton distributions. We show that the CS and DS components of u(x) + d(x) can be extracted by using recent data on the strangeness parton distribution, the CT10 global fit, and the lattice result of the ratio of the strange to u(d) moments in the disconnected insertion. The extracted CS and DS for u(x) + d(x) have a distinct Bjorken x dependence in qualitative agreement with expectation. The analysis also shows that the momentum fraction of u(x) + d(x) is about equally divided between the CS and DS at Q(2) = 2.5 GeV(2). Implications for the future global analysis of parton distributions are presented.

Controllable synthesis of VSB-5 microspheres and microrods: growth mechanism and selective hydrogenation catalysis.

Nanoporous VSB-5 nickel phosphate molecular sieves with relatively well controllable sizes and morphology of microspheres assembled from nanorods were synthesized at 140 degrees C over a short time in the presence of hexamethylenetetramine (HMT) by a facile hydrothermal method. The pH value, reaction time, and ratio of HMT to NaHPO2.H2O crucially influence the morphology and quality of the final products. By adjusting the pH value of the initial reaction solution, the morphology changes from disperse rods to microspheres assembled from rods and finally to a large quantity of fibers, and the diameters of the VSB-5 rods can be varied. The catalytic activity of VSB-5 in selective hydrogenation of several unsaturated organic compounds was tested. Nickel(II) in VSB-5 can selectively catalyze hydrogenation of C=C in trans-cinnamaldehyde and 3-methylcrotonaldehyde. In addition, since nitrobenzene (NB) and 2-chloronitrobenzene could be reduced to aniline (AN) and 2-chloroaniline with high selectivity, VSB-5 could have potential applications in synthesizing dyes, agrochemicals, and pharmaceuticals.