Nano-sized graphene flakes: insights from experimental synthesis and first principles calculations.

In this study, we proposed a cost-effective method for preparing graphene nano-flakes (GNFs) derived from carbon nanotubes (CNTs) via three steps (pressing, homogenization and sonication exfoliation processes). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), laser scattering, as well as ultraviolet-visible and photoluminescence (PL) measurements were carried out. The results indicated that the size of as-synthesized GNFs was approximately 40-50 nm. Furthermore, we also used first principles calculations to understand the transformation from CNTs to GNFs from the viewpoints of the edge formation energies of GNFs in different shapes and sizes. The corresponding photoluminescence measurements of GNFs were carried out in this work.

Identification of miRNAs and Their Targets in the Liverwort Marchantia polymorpha by Integrating RNA-Seq and Degradome Analyses.

Bryophytes (liverworts, hornworts and mosses) comprise the three earliest diverging lineages of land plants (embryophytes). Marchantia polymorpha, a complex thalloid Marchantiopsida liverwort that has been developed into a model genetic system, occupies a key phylogenetic position. Therefore, M. polymorpha is useful in studies aiming to elucidate the evolution of gene regulation mechanisms in plants. In this study, we used computational, transcriptomic, small RNA and degradome analyses to characterize microRNA (miRNA)-mediated pathways of gene regulation in M. polymorpha. The data have been integrated into the open access ContigViews-miRNA platform for further reference. In addition to core components of the miRNA pathway, 129 unique miRNA sequences, 11 of which could be classified into seven miRNA families that are conserved in embryophytes (miR166a, miR390, miR529c, miR171-3p, miR408a, miR160 and miR319a), were identified. A combination of computational and degradome analyses allowed us to identify and experimentally validate 249 targets. In some cases, the target genes are orthologous to those of other embryophytes, but in other cases, the conserved miRNAs target either paralogs or members of different gene families. In addition, the newly discovered Mpo-miR11707.1 and Mpo-miR11707.2 are generated from a common precursor and target MpARGONAUTE1 (LW1759). Two other newly discovered miRNAs, Mpo-miR11687.1 and Mpo-miR11681.1, target the MADS-box transcription factors MpMADS1 and MpMADS2, respectively. Interestingly, one of the pentatricopeptide repeat (PPR) gene family members, MpPPR_66 (LW9825), the protein products of which are generally involved in various steps of RNA metabolism, has a long stem-loop transcript that can generate Mpo-miR11692.1 to autoregulate MpPPR_66 (LW9825) mRNA. This study provides a foundation for further investigations of the RNA-mediated silencing mechanism in M. polymorpha as well as of the evolution of this gene silencing pathway in embryophytes.

Application of an Integrated Omics Approach for Identifying Host Proteins That Interact With Odontoglossum ringspot virus Capsid Protein.

The glutamic acid at position 100 (E(100)) in the capsid protein (CP) of Odontoglossum ringspot virus (ORSV) plays an important role in long-distance viral movement in Nicotiana benthamiana. The ORSV(E100A) mutant, which has a glutamic acid to alanine substitution, shows a loss of systemic infectivity in N. benthamiana. Transmission electron microscopy and size-exclusion chromatography assays showed that E(100) is essential for CP-CP interaction and viral particle assembly. To identify the ORSV triggering or response genes and CP-interacting proteins (CP-IP), an integrated omics approach based on next-generation sequencing and proteomics profiling was used in this study. The whole-transcriptomes of healthy and ORSV-infected leaves of N. benthamiana were analyzed, and the gene information was used to create a N. benthamiana protein database that was used for protein identification following mass spectrometry analysis. The integrated omics approach identified several putative host proteins that interact with ORSV CP(WT) and were categorized as photosystem subunits, defense-associated proteins, and cell division components. The expression pattern and CP interaction of these CP-IP were examined by semiquantitative reverse transcription polymerase chain reaction and an in vitro binding assay, respectively, to verify the in silico data. Among these proteins, a proteinase inhibitor of N. benthamiana (NbPI2) was highly associated with CP(E100A) as compared with CP(WT), and NbPI1 and NbPI2 were highly induced in ORSV-infected plants. NbPI1- and NbPI2-silenced plants (via a Tobacco rattle virus-induced gene-silencing system) did not exhibit a difference in ORSV infection. Thus, whether NbPI1 and NbPI2 play a role in plant immunity requires further investigation. In summary, the integrated omics approach provides massive and valuable information to identify the ORSV CP-IP and these CP-IP will help us to understand the movement of this virus and plant-virus interaction.

Multidimensional (0D to 3D) Alkaline-Earth Metal Diphosphonates: Synthesis, Structural Diversity, and Luminescence Properties.

A series of new alkaline-earth metal diphosphonate frameworks were successfully synthesized under solvothermal reaction condition (160 °C, 3 d) using 1-hydroxyethylidene-1,1-diphosphonic acid (CH3C(OH)(H2PO3)2, hedpH4) as a diphosphonate building block and Mg(II), Ca(II), Sr(II), or Ba(II) ions as alkaline-earth metal ion centers in water, dimethylformamide, and/or EtOH media. These diphosphonate frameworks, (H2NMe2)4[Mg(hedpH2)3]·3H2O (1), (H2NMe2)2[Ca(hedpH2)2] (2), (H2NMe2)2[Sr3(hedpH2)4(H2O)2] (3), and [Ba3(hedpH2)3]·H2O (4) exhibited interesting structural topologies (zero-, one-, two-, and three-dimensional (0D, 1D, 2D, and 3D, respectively)), which are mainly depending on the metal ions and the solvents used in the synthesis. The single-crystal analysis of these newly synthesized compounds revealed that 1 was a 0D molecule, 2 has 1D chains, 3 was a 3D molecule, and 4 has 2D layers. All compounds were further characterized using thermogravimetric analysis, solid-state (31)P NMR, powder X-ray diffraction analysis, UV-vis spectra, and infrared spectroscopy. In addition, Eu(III)- and Tb(III)-doped compounds of 1-4, namely, (H2NMe2)4[Ln(x)Mg(1-x)(hedpH2)2(hedpH(2-x))]·3H2O (1Ln), (H2NMe2)2[Ln(x)Ca(1-x)(hedpH2)(hedpH(2-x))] (2Ln), (H2NMe2)2[Ln(x)Sr(3-x)(hedpH2)3(hedpH(2-x))(H2O)2] (3Ln), and [Ln(x)Ba(3-x)(hedpH2)2(hedpH(2-x))]·H2O (4Ln) (where Ln = Eu, Tb), were synthesized, and their photoluminescence properties were studied. The quantum yield of 1Eu-4Eu was measured with reference to commercial red phosphor, Y2O2S:Eu(3+) (YE), and the quantum yield of terbium-doped compounds 1Tb-4Tb was measured with reference to commercial green-emitting phosphor CeMgAl10O17:Tb(3+). Interestingly, the compound 2Eu showed very high quantum yield of 92.2%, which is better than that of the reference commercial red phosphor, YE (90.8%).

Genetic analyses of the FRNK motif function of Turnip mosaic virus uncover multiple and potentially interactive pathways of cross-protection.

Cross-protection triggered by a mild strain of virus acts as a prophylaxis to prevent subsequent infections by related viruses in plants; however, the underling mechanisms are not fully understood. Through mutagenesis, we isolated a mutant strain of Turnip mosaic virus (TuMV), named Tu-GK, that contains an Arg182Lys substitution in helper component-proteinase (HC-Pro(K)) that confers complete cross-protection against infection by a severe strain of TuMV in Nicotiana benthamiana, Arabidopsis thaliana Col-0, and the Arabidopsis dcl2-4/dcl4-1 double mutant defective in DICER-like ribonuclease (DCL)2/DCL4-mediated silencing. Our analyses showed that HC-Pro(K) loses the ability to interfere with microRNA pathways, although it retains a partial capability for RNA silencing suppression triggered by DCL. We further showed that Tu-GK infection triggers strong salicylic acid (SA)-dependent and SA-independent innate immunity responses. Our data suggest that DCL2/4-dependent and -independent RNA silencing pathways are involved, and may crosstalk with basal innate immunity pathways, in host defense and in cross-protection.

A study on luminescence properties and energy transfer mechanism for NaCaY(PO4)2:Eu²âº,Mn²âº phosphors for LED applications.

A color-tunable NaCaY(PO4)2:Eu²âº,Mn²âº, was synthesized by a solid state reaction. NaCaY(PO4)2 crystallizes in the hexagonal structure system with space group of P6222 and Z = 1. The NaCaY(PO4)2:Eu²âº exhibits blue-greenish emission and broad excitation bands corresponding to the allowed f→d electronic transition of Eu²âº. In addition, via the design of efficient energy transfer from Eu²âº to Mn²âº, a high quality of white-emitting light could be generated in the optimized composition of NaCaY(PO4)2:1%Eu²âº, 0.5%Mn²âº with CIE coordinates of (0.3389,0.3531) and CRI of 82, which is superior than that of blue chip and YAG phosphors. The results indicate that as-synthesized NaCaY(PO4)2:Eu²âº,Mn²âº phosphors exhibits the potential to be an n-UV convertible phosphor.

New metal-free one-pot synthesis of α-2-deoxy-Ulosides by microwave-assisted double Michael Addition of ß-enamino ketones.

New metal-free one-pot synthesis of α-2-deoxy-ulosides in moderate to good yields by microwave-assisted double Michael addition of various O-nucleophiles to ß-enamino ketones in the presence of 12 N HCl. These glycosyl additions occurred with high α-stereoselectivity and were complete in 10-25 min in 51-93% yield. In addition, high α-stereoselectivity was also observed when S-nucleophiles were examined.

Investigating the Viral Suppressor HC-Pro Inhibiting Small RNA Methylation through Functional Comparison of HEN1 in Angiosperm and Bryophyte.

In plants, HEN1-facilitated methylation at 3' end ribose is a critical step of small-RNA (sRNA) biogenesis. A mutant of well-studied Arabidopsis HEN1 (AtHEN1), hen1-1, showed a defective developmental phenotype, indicating the importance of sRNA methylation. Moreover, Marchantia polymorpha has been identified to have a HEN1 ortholog gene (MpHEN1); however, its function remained unfathomed. Our in vivo and in vitro data have shown MpHEN1 activity being comparable with AtHEN1, and their substrate specificity towards duplex microRNA (miRNA) remained consistent. Furthermore, the phylogenetic tree and multiple alignment highlighted the conserved molecular evolution of the HEN1 family in plants. The P1/HC-Pro of the turnip mosaic virus (TuMV) is a known RNA silencing suppressor and inhibits HEN1 methylation of sRNAs. Here, we report that the HC-Pro physically binds with AtHEN1 through FRNK motif, inhibiting HEN1's methylation activity. Moreover, the in vitro EMSA data indicates GST-HC-Pro of TuMV lacks sRNA duplex-binding ability. Surprisingly, the HC-Pro also inhibits MpHEN1 activity in a dosage-dependent manner, suggesting the possibility of interaction between HC-Pro and MpHEN1 as well. Further investigations on understanding interaction mechanisms of HEN1 and various HC-Pros can advance the knowledge of viral suppressors.

Investigation of the effects of P1 on HC-pro-mediated gene silencing suppression through genetics and omics approaches.

BACKGROUND: Posttranscriptional gene silencing (PTGS) is one of the most important mechanisms for plants during viral infection. However, viruses have also developed viral suppressors to negatively control PTGS by inhibiting microRNA (miRNA) and short-interfering RNA (siRNA) regulation in plants. The first identified viral suppressor, P1/HC-Pro, is a fusion protein that was translated from potyviral RNA. Upon infecting plants, the P1 protein itself is released from HC-Pro by the self-cleaving activity of P1. P1 has an unknown function in enhancing HC-Pro-mediated PTGS suppression. We performed proteomics to identify P1-interacting proteins. We also performed transcriptomics that were generated from Col-0 and various P1/HC-Pro-related transgenic plants to identify novel genes. The results showed several novel genes were identified through the comparative network analysis that might be involved in P1/HC-Pro-mediated PTGS suppression. RESULTS: First, we demonstrated that P1 enhances HC-Pro function and that the mechanism might work through P1 binding to VERNALIZATION INDEPENDENCE 3/SUPERKILLER 8 (VIP3/SKI8), a subunit of the exosome, to interfere with the 5'-fragment of the PTGS-cleaved RNA degradation product. Second, the AGO1 was specifically posttranslationally degraded in transgenic Arabidopsis expressing P1/HC-Pro of turnip mosaic virus (TuMV) (P1/HCTu plant). Third, the comparative network highlighted potentially critical genes in PTGS, including miRNA targets, calcium signaling, hormone (JA, ET, and ABA) signaling, and defense response. CONCLUSION: Through these genetic and omics approaches, we revealed an overall perspective to identify many critical genes involved in PTGS. These new findings significantly impact in our understanding of P1/HC-Pro-mediated PTGS suppression.

Green and facile synthesis of few-layer graphene via liquid exfoliation process for Lithium-ion batteries.

A green and facile method using jet cavitation (JC) was utilized to prepare few layer graphene (FLG) derived from artificial graphite delamination without adding any strong acids and oxidants. The JC method not only provides high quality FLG with high yield but also demonstrate excellent electrochemical performance as anode materials for Li-ion batteries. Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) as well as BET isotherms and XPS are carried out in this study. The results of atomic force microscopy (AFM) further revealed that up to 85% of the prepared FLG were less than 10 layers. This exfoliation process happened mainly due to the cavitation-induced intensive tensile stress acting on the layered materials. Electrochemical measurements demonstrate that graphite anode delivered only 240 mAh/g while FLG anode achieved more than 322 mAh/g at 5C rate test. These results indicate that JC method not only paves the way for cheaper and safer production of graphene but also holds great potential applications in energy-related technology.

Synchronous Appendiceal Triple Primary Neoplasms and Acute Abdomen-A Case Report.

Abdominal pain is a very common presenting symptom in the emergency department (ED). To reach an accurate diagnosis one must consider the possibility of multiple conditions that might cause the presenting symptom. We reported a female patient who came to our ED due to aggravated right lower quadrant abdominal pain for several hours. Multiple diagnosis of right T11 herpes zoster, right urolithiasis with hydronephrosis, appendiceal collision tumors of adenocarcinoma arising from adenoma and neuroendocrine tumor as well as leiomyoma in the surrounding adipose tissue were made. Histological examination and immunohistochemistrysupport these three lesions as separate entities. This case is unique because her multiple combined illness present as abdominal pain. Each one could be the cause of chief complaint, across dermatologic, urologic and neoplastic disorders.

Phellodendron chinense Schneid: A novel yellow-emitting luminescent material for white light-emitting diodes.

To facilitate the next generation of environmental material for white light emitting diodes, the discovery of natural luminesce is essential. In this study, we disclose a rare-earth free and yellow-emission phosphor, Phellodendron, which could be both excited by near ultraviolet light and blue light. The new yellow phosphor is obtained by extraction of Phellodendron chinense Schneid. The emission wavelength, full width at half maximum and CIE coordinates of extracted Phellodendron are 540 nm, 120 nm and (0.41, 0.55), respectively. The corresponding luminescent properties of Phellodendron are characterized by PL, PLE, reflection spectra, FITR and decay lifetime. Surprising thing is luminous intensity of Phellodendron phosphors excited at 380 nm was stronger than YAG:Ce phosphor by more than 139%. In addition, we firstly introduce the yellow phosphor in white LED fabrication by combining blue chip and Y3Al5O12:Ce3+ phosphor, to create warm white. For comparison, red-emission CaAlSiN3:Eu2+ phosphors are also introduced for LED package tests. The results demonstrate that Phellodendron is a potential candidate for white LED applications.

The convergence of autophagy, small RNA and the stress response - implications for transgenerational epigenetic inheritance in plants.

Recent discoveries in eukaryotes have shown that autophagy-mediated degradation of DICER and ARGONAUTE (AGO), the proteins involved in post-transcriptional gene silencing (PTGS), can occur in response to viral infection and starvation. In plants, a virally encoded protein P0 specifically interacts with AGO1 and enhances degradation through autophagy, resulting in suppression of gene silencing. In HeLa cells, DICER and AGO2 protein levels decreased after nutrient starvation or after treatment to increase autophagy. Environmental exposures to viral infection and starvation have also recently been shown to sometimes not only induce a stress response in the exposed plant but also in their unexposed progeny. These, and other cases of inherited stress response in plants are thought to be facilitated through transgenerational epigenetic inheritance, and the mechanism involves the PTGS and transcriptional gene silencing (TGS) pathways. These recent discoveries suggest that the environmentally-induced autophagic degradation of the PTGS and TGS components may have significant effects on inherited stress responses.

Improving initial infectivity of the Turnip mosaic virus (TuMV) infectious clone by an mini binary vector via agro-infiltration.

BACKGROUND: The in vivo infectious clone of Turnip mosaic virus (TuMV), p35S-TuMV, was used on plant pathology research for many years. To activate p35S-TuMV, the plasmid was mechanically introduced to the local lesion host Chenopodium quinoa. However, low infectivity occurred when the TuMV from C. quinoa was transferred to the systemic host Nicotiana benthamiana. RESULTS: To increase the efficiency of initial infectivity on N. benthamiana, the expression of the TuMV infectious clone by a binary vector that directly activates viral RNA through agro-infiltration is considered to be a good alternative. The size of the binary vector by agro-infiltration is usually large and its backbone has numerous restriction sites that increase difficulty for construction. In this study, we attempted to construct a mini binary vector (pBD003) with less restriction sites. The full-length cDNA of TuMV genome, with or without green fluorescence protein, was inserted in pBD003 to generate pBD-TuMV constructs, which were then individually introduced to N. benthamiana plants by agro-infiltration. Symptom development and ELISA positivity with TuMV antiserum indicated that the pBD-TuMV constructs are infectious. Moreover, the initial infectivity of a mild strain TuMV-GK, which contains an R182K mutation on HC-Pro, constructed in the pBD003 vector was significantly increased by agro-infiltration. CONCLUSION: Thus, we concluded that the newly constructed mini binary vector provides a more feasible tool for TuMV researches in areas, such as creating a mild strain for cross-protection, or a viral vector for foreign gene expression. In addition, the multiple cloning sites will be further cloned in pBD003 for convenience in constructing other viral infectious clones.