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Carbon quantum dots (CQDs) have emerged as promising materials for optoelectronic applications on account of carbon's intrinsic merits of high stability, low cost, and environment-friendliness. However, the CQDs usually give broad emission with full width at half maximum exceeding 80 nm, which fundamentally limit their display applications. Here we demonstrate multicolored narrow bandwidth emission (full width at half maximum of 30 nm) from triangular CQDs with a quantum yield up to 54-72%. Detailed structural and optical characterizations together with theoretical calculations reveal that the molecular purity and crystalline perfection of the triangular CQDs are key to the high color-purity. Moreover, multicolored light-emitting diodes based on these CQDs display good stability, high color-purity, and high-performance with maximum luminance of 1882-4762 cdm-2 and current efficiency of 1.22-5.11 cd A-1. This work will set the stage for developing nextgeneration high-performance CQDs-based light-emitting diodes. [ABSTRACT FROM AUTHOR]

Epigenetic modification of the mammalian genome by DNA methylation (5-methylcytosine) has a profound impact on chromatin structure, gene expression and maintenance of cellular identity. The recent demonstration that members of the Ten-eleven translocation (Tet) family of proteins can convert 5-methylcytosine to 5-hydroxymethylcytosine raised the possibility that Tet proteins are capable of establishing a distinct epigenetic state. We have recently demonstrated that Tet1 is specifically expressed in murine embryonic stem (ES) cells and is required for ES cell maintenance. Using chromatin immunoprecipitation coupled with high-throughput DNA sequencing, here we show in mouse ES cells that Tet1 is preferentially bound to CpG-rich sequences at promoters of both transcriptionally active and Polycomb-repressed genes. Despite an increase in levels of DNA methylation at many Tet1-binding sites, Tet1 depletion does not lead to downregulation of all the Tet1 targets. Interestingly, although Tet1-mediated promoter hypomethylation is required for maintaining the expression of a group of transcriptionally active genes, it is also involved in repression of Polycomb-targeted developmental regulators. Tet1 contributes to silencing of this group of genes by facilitating recruitment of PRC2 to CpG-rich gene promoters. Thus, our study not only establishes a role for Tet1 in modulating DNA methylation levels at CpG-rich promoters, but also reveals a dual function of Tet1 in promoting transcription of pluripotency factors as well as participating in the repression of Polycomb-targeted developmental regulators. [ABSTRACT FROM AUTHOR]

X-linked mental retardation (XLMR) is a complex human disease that causes intellectual disability. Causal mutations have been found in approximately 90 X-linked genes; however, molecular and biological functions of many of these genetically defined XLMR genes remain unknown. PHF8 (PHD (plant homeo domain) finger protein 8) is a JmjC domain-containing protein and its mutations have been found in patients with XLMR and craniofacial deformities. Here we provide multiple lines of evidence establishing PHF8 as the first mono-methyl histone H4 lysine 20 (H4K20me1) demethylase, with additional activities towards histone H3K9me1 and me2. PHF8 is located around the transcription start sites (TSS) of ∼7,000 RefSeq genes and in gene bodies and intergenic regions (non-TSS). PHF8 depletion resulted in upregulation of H4K20me1 and H3K9me1 at the TSS and H3K9me2 in the non-TSS sites, respectively, demonstrating differential substrate specificities at different target locations. PHF8 positively regulates gene expression, which is dependent on its H3K4me3-binding PHD and catalytic domains. Importantly, patient mutations significantly compromised PHF8 catalytic function. PHF8 regulates cell survival in the zebrafish brain and jaw development, thus providing a potentially relevant biological context for understanding the clinical symptoms associated with PHF8 patients. Lastly, genetic and molecular evidence supports a model whereby PHF8 regulates zebrafish neuronal cell survival and jaw development in part by directly regulating the expression of the homeodomain transcription factor MSX1/MSXB, which functions downstream of multiple signalling and developmental pathways. Our findings indicate that an imbalance of histone methylation dynamics has a critical role in XLMR. [ABSTRACT FROM AUTHOR]

Histones are characterized by numerous posttranslational modifications that influence gene transcription. However, because of the lack of global distribution data in higher eukaryotic systems, the extent to which gene-specific combinatorial patterns of histone modifications exist remains to be determined. Here, we report the patterns derived from the analysis of 39 histone modifications in human CD4+ T cells. Our data indicate that a large number of patterns are associated with promoters and enhancers. In particular, we identify a common modification module consisting of 17 modifications detected at 3,286 promoters. These modifications tend to colocalize in the genome and correlate with each other at an individual nucleosome level. Genes associated with this module tend to have higher expression, and addition of more modifications to this module is associated with further increased expression. Our data suggest that these histone modifications may act cooperatively to prepare chromatin for transcriptional activation. [ABSTRACT FROM AUTHOR]

Abstract The Arabidopsis CBF proteins activate expression of a set of genes whose upstream regulatory sequences typically harbor one or more copies of the CRT/DRE low temperature cis-acting DNA regulatory element. Using domain swap experiments in both yeast and Arabidopsis we show that the NH3-terminal 115 amino acids direct CBF1 to target genes and the COOH-terminal 98 amino acids function in trans-activation. Mutational analysis through the COOH-terminus using truncation and alanine-substitution mutants in yeast revealed four motifs that contribute positively towards activation. Overexpression of mutants in plants support this conclusion and also indicated that disruption of a single motif did not seriously compromise activity unless combined with the disruption of a second. These motifs consist of clusters of hydrophobic residues which are delimited from one another by short stretches of Asp, Glu, Pro and other residues favoring the formation of loops. This structural pattern is conserved across plant taxa as revealed through alignment of Arabidopsis CBF1 with homologous sequences from a diverse array of plant species. Overexpression in plants of the CBF1 COOH-terminus as a fusion with the yeast GAL4 DNA binding domain also resulted in severe stunting of growth, a phenotype which was alleviated if the activation domain was rendered ineffective. Taken together these results suggest that high level overexpression of an active, CBF activation domain compromises plant growth. [ABSTRACT FROM AUTHOR]

Focuses on a study that found that the expression of two insect-resistant genes in transgenic tobacco plants results in added protection against both cotton bollworm and aphids. Expression of the synthesized Bacillus thuringiensis insecticidal protein gene crylA (b&c) and the synthesized gene GNA; Methodology of the study; Results and discussion; Conclusion.

The cricoarytenoid relationship presented with spiral computed tomography was demonstrated and the reconstruction of arytenoid dislocation was presented by using multiplanar reconstruction algorithms. Fifteen patients with arytenoid dislocation documented by fiberoptic laryngoscopy and strobovideolaryngoscopy and 10 normal persons were displayed by spiral computed tomography (CT). A making design of our own had been used to diagnose arytenoid dislocation on axial CT image. Results showed that dislocation of cricoarytenoid joint was consistently demonstrated on several of the overlapping thin axial reconstructions in each of the 15 patients, in whom asymmetry of the bilateral cricoarytenoid joints was noted on axial images. It was found that on the glottic-fissure level the basal angle on abnormal side was larger in 8 patients than that on the normal side and smaller in 7 patients in patient group, whereas right basal angle was equal to the left in 8 subjects, except 2 in control group. There was statistically significant difference in the number of the equal to two basal angles of glottic fissure between control group and patient group ( P<0.025). High-quality sagittal and coronal reconstructive images often were helpful in confirming or clarifying the complex arytenoid orientations. The findings that two-side basal angle was not equal in triangle of glottic fissure can be used as an objective parameter to diagnose arytenoid dislocation. Spiral CT is a useful adjunct in the diagnosis and treatment of dislocation of cricoarytenoid joint. [ABSTRACT FROM AUTHOR]

To assess the pharyngeal presentations and the diagnostic value of thyroid SPECT and thyroid fine needle aspiratory biopsy (FNAB) in subacute thyroiditis (SAT) as seen initially in ENT department, 30 patients, during the course of SAT, were examined for pharyngeal symptoms and tested for serum T3, T4 level. The thyroid SPECT imaging or thyroid FNAB were performed. Our results showed that, of the 30 patients, 21 had sore throat of various degrees, and 9 had abnormal sensation of throat. Six were diagnosed as having SAT by only SPECT, in the remaining 24, the final diagnoses was established by SPECT combined with FNAB. Two of them were finally diagnosed as having SAT by trial treatment with oral prednisone. It is concluded that sore throat and abnormal sensation of pharynx are the important presentations of SAT, and thyroid SPECT imaging and thyroid FNAB are valuable in diagnosing SAT. [ABSTRACT FROM AUTHOR]