MicroRNAs (miRNAs), i.e. small non-coding RNA molecules (∼22 nt), can bind to one or more target sites on a gene transcript to negatively regulate protein expression, subsequently controlling many cellular mechanisms. A current and curated collection of miRNA–target interactions (MTIs) with experimental support is essential to thoroughly elucidating miRNA functions under different conditions and in different species. As a database, miRTarBase has accumulated more than 3500 MTIs by manually surveying pertinent literature after data mining of the text systematically to filter research articles related to functional studies of miRNAs. Generally, the collected MTIs are validated experimentally by reporter assays, western blot, or microarray experiments with overexpression or knockdown of miRNAs. miRTarBase curates 3576 experimentally verified MTIs between 657 miRNAs and 2297 target genes among 17 species. miRTarBase contains the largest amount of validated MTIs by comparing with other similar, previously developed databases. The MTIs collected in the miRTarBase can also provide a large amount of positive samples to develop computational methods capable of identifying miRNA–target interactions. miRTarBase is now available on http://miRTarBase.mbc.nctu.edu.tw/, and is updated frequently by continuously surveying research articles.

Numerous regulatory structural motifs have been identified as playing essential roles in transcriptional and post-transcriptional regulation of gene expression. RegRNA is an integrated web server for identifying the homologs of regulatory RNA motifs and elements against an input mRNA sequence. Both sequence homologs and structural homologs of regulatory RNA motifs can be recognized. The regulatory RNA motifs supported in RegRNA are categorized into several classes: (i) motifs in mRNA 5′-untranslated region (5′-UTR) and 3′-UTR; (ii) motifs involved in mRNA splicing; (iii) motifs involved in transcriptional regulation; (iv) riboswitches; (v) splicing donor/acceptor sites; (vi) inverted repeats; and (vii) miRNA target sites. The experimentally validated regulatory RNA motifs are extracted from literature survey and several regulatory RNA motif databases, such as UTRdb, TRANSFAC, alternative splicing database (ASD) and miRBase. A variety of computational programs are integrated for identifying the homologs of the regulatory RNA motifs. An intuitive user interface is designed to facilitate the comprehensive annotation of user-submitted mRNA sequences. The RegRNA web server is now available at .

Organic light-emitting devices (OLEDs) hold great potential for application in flat-panel displays due to rapid progress in material design and device fabrication in recent years. [1±4] Red, green, and blue emissions of matching efficiencies are required for a full-color display. Greater success has been achieved in the development of a green emitter than that of red one in both fluorescent and phosphorescent displays. For example, devices based on green fluorescent dopant C545T [5] can reach a luminance efficiency > 10 cd A ±1 . In contrast, the best red OLEDs reported [6±10] can only reach~3 cd A ±1 and external quantum efficiencies less than 1 %. OLEDs based on phosphorescent materials [11] can significantly improve electroluminescence performance because both singlet and triplet excitons can be harvested for light emission. Theoretically, the internal quantum efficiency of phosphorescent emitters can approach 100 %. Unfortunately, most of phosphorescent emitters have a long lifetime (> 10 ls), which results in saturation of emissive sites at increasing currents. The first red phosphorescent material was reported for complexes of the type EuL 3 , where L denotes a ligand.[12] The long lifetime of the electronically excited europium(III) (350 ls) leads to dominant triplet±triplet (T±T) annihilation at high currents, and the maximum efficiency is only 1.4 %. Although platinum(II) octaethylporphyrin (PtOEP) doped into 4,4,N,N¢-dicarbazolebiphenyl (CBP) shows an external quantum efficiency g ext = 5.6 %, for a red phosphor, [4,13] the occurrence of T±T annihilation is inevitable at high currents (g ext = 0.5 % at 100 mA cm ±2 ) due to its relatively long phosphorescent lifetime (50±80 ls). Recently, a more efficient red phosphor has been reported, Ir(btp) 2 (acac) [14] (btp = 2-(2¢-benzo[4.5-a]thienyl)pyridinato; acac = acetylacetonate), that achieved an efficiency of g ext = 7.0 % at low current. The relatively short phosphorescent lifetime (4 ls) significantly improves the external efficiency at high currents (g ext = 2.5 % at 100 mA cm ±2 ). A short phosphorescence lifetime is crucial for the performance of a phosphorescent material, particularly its maximum brightness and efficiency at high currents. In this communication, we wish to report a series of efficient red phosphorescent emitters based on iridium 1-(phenyl)isoquinoline complexes which show strong electroluminescence (EL) brightness and efficiency, even at high currents. Scheme 1 outlines the synthetic protocol for red phosphorescent complexes: Ir(piq) 2 (acac), Ir(piq-F) 2 (acac), and Ir(piq-F) 3 , with piq and piq-F representing the 1-(phenyl)isoquinoline and 2-(4¢-fluorophenyl)isoquinoline ligands, respectively. The para-fluoro substituent of Ir(piq-F) 2 (acac) and Ir(piq-F) 3 is used to tune emission wavelength without loss of performance efficiency.[15] 1-(Phenyl)isoquinoline ligand was prepared from the reaction of isoquinoline with the corresponding phenyl magnesium bromide. The complexes Ir-(piq) 2 (acac) and Ir(piq-F) 2 (acac) were ...

BackgroundMicroRNAs (miRNAs) are small non-coding RNA molecules that are ~22-nt-long sequences capable of suppressing protein synthesis. Previous research has suggested that miRNAs regulate 30% or more of the human protein-coding genes. The aim of this work is to consider various analyzing scenarios in the identification of miRNA-target interactions, as well as to provide an integrated system that will aid in facilitating investigation on the influence of miRNA targets by alternative splicing and the biological function of miRNAs in biological pathways.ResultsThis work presents an integrated system, miRTar, which adopts various analyzing scenarios to identify putative miRNA target sites of the gene transcripts and elucidates the biological functions of miRNAs toward their targets in biological pathways. The system has three major features. First, the prediction system is able to consider various analyzing scenarios (1 miRNA:1 gene, 1:N, N:1, N:M, all miRNAs:N genes, and N miRNAs: genes involved in a pathway) to easily identify the regulatory relationships between interesting miRNAs and their targets, in 3'UTR, 5'UTR and coding regions. Second, miRTar can analyze and highlight a group of miRNA-regulated genes that participate in particular KEGG pathways to elucidate the biological roles of miRNAs in biological pathways. Third, miRTar can provide further information for elucidating the miRNA regulation, i.e., miRNA-target interactions, affected by alternative splicing.ConclusionsIn this work, we developed an integrated resource, miRTar, to enable biologists to easily identify the biological functions and regulatory relationships between a group of known/putative miRNAs and protein coding genes. miRTar is now available at http://miRTar.mbc.nctu.edu.tw/.

A new series of luminescent platinum(II) azolate complexes with a formula of [Pt(NwedgeN)(2)], in which NwedgeN = mppz (1), bppz (2a), bzpz (2b), bmpz (2c), bqpz (2d), fppz (3a), hppz (3b), bptz (4), hptz (5), were synthesized, and their photophyscial properties were examined. Single-crystal X-ray diffraction studies of 2c and 3b revealed a planar molecular geometry, in which the NwedgeN chelates adopt a trans configuration and show notable interligand C-H...N hydrogen bonding within the complex. Interesting intermolecular interactions were observed in the solid state. Complex 2c formed a slipped-stack structure with a Pt...Pt separation distance of 6.432 Angstroms, while complex 3b showed a columnar stacking with the molecules oriented in an alternating order in relation to the chain axis, giving a much reduced Pt...Pt distance of 3.442 Angstroms. The lowest absorption band for all complexes revealed strong state mixings between the singlet and triplet (MLCT and intraligand pipi) manifolds. Complexes 1 and 2 showed mixed (3)MLCT and (3)pipi phosphorescence in fluid solution. While radiationless deactivation was apparently dominant for complexes 3-5 in solution, resulting in rather weak emission, strong phosphorescence was observed in the room-temperature solid state with the peak wavelength being significantly red shifted compared to that in solution. The emission nature has been tentatively assigned to be (3)MMLCT in character. OLED devices with a multilayer configuration of ITO/NPB/CBP:2a/BCP/Alq(3)/LiF/Al were successfully fabricated using a CBP layer doped with various amount of 2a, ranging from 6 to 100%, as the emitting layer. A substantial red shift with increasing doping concentrations was observed in electroluminescence. With a neat film of 2a, the device showed a green emission with lambda(max) at 556 nm and an external QE of approximately 1.6% at a driving current of 20 mA. Similarly, for the device using a neat film of 3a, an electroluminescence centered at 616 nm with a slightly reduced external QE of approximately 2.1% was recorded. Aggregation of platinum(II) complexes in the solid state was proposed to account for the large red-shift in electroluminescence.

The titled dipolar hybrids bearing a central quinoxaline-fused dibenzosuberene optoelectronic unit with functional C5 and C8 appendages and spiro-fluorene junction act as fluorescent bipolar OLED chameleons. The emission colors can be tuned from blue, green, yellow, to red with operation brightness of 205, 1268, 1542, and 1102 cd/m2, respectively, at 20 mA/cm2.

Heteroleptic cyclometalated iridium(III) complexes featuring lepidine-based ligands and acetyl acetone auxiliary ligand are synthesized. Multiple lowest energy absorption bands are observed for these complexes indicating substantial mixing of the singlet and triplet levels. All the complexes emit orange or red color in dichloromethane solutions with lifetimes in the range 1.6-3.7 micros. The emission in the complexes probably originates from the (3)MLCT state. The complexes are applied as emitting guests in LED devices of the structure ITO/HTL(BPAPF or NPB)/6% Ir in CBP/BCP/Alq(3)/LiF/Al. They exhibit excellent device characteristics with an orange to red EL profile.

A series of dicarbazolyl derivatives bridged by various aromatic spacers and decorated with peripheral diarylamines were synthesized using Ullmann and Pd‐catalyzed C–N coupling procedures. These derivatives emit blue light in solution. In general, they possess high glass‐transition temperatures (Tg > 125 °C) which vary with the bridging segment and methyl substitution on the peripheral amine. Double‐layer organic light‐emitting devices were successfully fabricated using these molecules as hole‐transporting and emitting materials. Devices of the configuration ITO/HTL/TPBI/Mg:Ag (ITO: indium tin oxide; HTL: hole‐transporting layer; TPBI: 1,3,5‐tris(N‐phenylbenzimidazol‐2‐yl)benzene) display blue emission from the HTL layer. The EL spectra of these devices appear slightly distorted due to the exciplex formation at the interfaces. However, for the devices of the configuration ITO/HTL/Alq3/Mg:Ag (Alq3 = tris(8‐hydroxyquinoline)aluminum) a bright green light from the Alq3 layer was observed. This clearly demonstrates the facile hole‐transporting property of the materials described here.