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Find video protocols related to scientific articles indexed in Pubmed.
Synergistic Coupling of Fluorescent "Turn-Off" with Spectral Overlap Modulated FRET for Ratiometric Ag(+) Sensor.
Inorg Chem
PUBLISHED: 10-27-2014
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A useful strategy for ratiometric fluorescent detecting of Ag(+) is demonstrated. Upon selective binding of Ag(+) to a BODIPY-porphyrin dyad (1), the synergistic coupling of two functions, namely the suppressing of FRET from BODIPY donor to porphyrin acceptor and the fluorescence quenching of porphyrin acceptor, leads to exceptionally large changes in the intensity ratio of two distinct emissions (F513/F654) which allow for the ratiometric detecting of Ag(+) with excellent sensitivity in solution and living cells.
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CRISPR/Cas-mediated genome editing in the rat via direct injection of one-cell embryos.
Nat Protoc
PUBLISHED: 09-25-2014
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Conventional embryonic stem cell (ESC)-based gene targeting, zinc-finger nuclease (ZFN) and transcription activator-like effector nuclease (TALEN) technologies are powerful strategies for the generation of genetically modified animals. Recently, the CRISPR/Cas system has emerged as an efficient and convenient alternative to these approaches. We have used the CRISPR/Cas system to generate rat strains that carry mutations in multiple genes through direct injection of RNAs into one-cell embryos, demonstrating the high efficiency of Cas9-mediated gene editing in rats for simultaneous generation of compound gene mutant models. Here we describe a stepwise procedure for the generation of knockout and knock-in rats. This protocol provides guidelines for the selection of genomic targets, synthesis of guide RNAs, design and construction of homologous recombination (HR) template vectors, embryo microinjection, and detection of mutations and insertions in founders or their progeny. The procedure from target design to identification of founders can take as little as 6 weeks, of which <10 d is actual hands-on working time.
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Molecular encoder-decoder based on an assembly of graphene oxide with dye-labelled DNA.
Chem. Commun. (Camb.)
PUBLISHED: 06-11-2014
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A general strategy was developed to fabricate 2-to-1, 4-to-2 and 8-to-3 molecular encoders and a 1-to-2 decoder by assembling graphene oxide with various dye-labeled DNAs.
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Label-free fluorescence polarization detection of pyrophosphate based on 0D/1D fast transformation of CdTe nanostructures.
Analyst
PUBLISHED: 05-28-2014
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A novel and label-free fluorescence polarization (FP) method for the determination of pyrophosphate (PPi) is developed based on the change in FP signals during fast reversible transformation between CdTe zero-dimensional (0D) nanocrystals (NCs) and one-dimensional (1D) nanorods (NRs) induced by addition of PPi. Under optimum conditions, the FP ratio was linearly proportional to the logarithm of the concentration of PPi between 2.0 × 10(-5) and 1.0 × 10(-9) M with a detection limit of 8.0 × 10(-10) M. The developed method, with high signal selectivity and stability, was successfully applied to the detection of PPi in human urine samples.
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Maize Elongin C interacts with the viral genome-linked protein, VPg, of Sugarcane mosaic virus and facilitates virus infection.
New Phytol.
PUBLISHED: 03-25-2014
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The viral genome-linked protein, VPg, of potyviruses is involved in viral genome replication and translation. To determine host proteins that interact with Sugarcane mosaic virus (SCMV) VPg, a yeast two-hybrid screen was used and a maize (Zea mays) Elongin C (ZmElc) protein was identified. ZmELC transcript was observed in all maize organs, but most highly in leaves and pistil extracts, and ZmElc was present in the cytoplasm and nucleus of maize cells in the presence or absence of SCMV. ZmELC expression was increased in maize tissue at 4 and 6 d post SCMV inoculation. When ZmELC was transiently overexpressed in maize protoplasts the accumulation of SCMV RNA was approximately doubled compared with the amount of virus in control protoplasts. Silencing ZmELC expression using a Brome mosaic virus-based gene silencing vector (virus-induced gene silencing) did not influence maize plant growth and development, but did decrease RNA accumulation of two isolates of SCMV and host transcript encoding ZmeIF4E during SCMV infection. Interestingly, Maize chlorotic mottle virus, from outside the Potyviridae, was increased in accumulation after silencing ZmELC expression. Our results describe both the location of ZmElc expression in maize and a new activity associated with an Elc: support of potyvirus accumulation.
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Spontaneous development of autoimmune uveitis Is CCR2 dependent.
Am. J. Pathol.
PUBLISHED: 02-07-2014
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Development of novel strategies to treat noninfectious posterior uveitis is an ongoing challenge, in part because of limited availability of animal models that mimic the naturally occurring disease in humans. Mice deficient in the autoimmune regulatory gene Aire develop a spontaneous T-cell and macrophage-mediated autoimmune uveitis that closely recapitulates human endogenous uveitis and thus provide a useful model for mechanistic and therapeutic investigations. Lymphocytic and mononuclear infiltration of the retina in Aire knockout (KO) mice triggers the onset of uveitis from initial retinal inflammation to eventual destruction of the neuroretina with loss of photoreceptors. The C-C chemokine receptor type 2 protein (CCR2) functions in directing monocyte and macrophage migration to inflamed tissues via interaction with monocyte chemotactic proteins. Using the Aire KO mouse model, we demonstrated an essential role for CCR2 in the pathogenesis of autoimmune-mediated uveitis. Loss of functional CCR2 effectively reduced immune cell infiltration and rescued the retina from destruction. CCR2-dependent migration of bone marrow-derived cells provided the driving force for retinal inflammation, with CCR2-expressing mononuclear cells contributing to retinal damage via recruitment of CD4(+) T cells. These studies identify the CCR2 pathway as a promising therapeutic target that may prove an effective approach to treat uveitis associated with autoimmunity.
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Virus-independent and common transcriptome responses of leafhopper vectors feeding on maize infected with semi-persistently and persistent propagatively transmitted viruses.
BMC Genomics
PUBLISHED: 01-29-2014
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Insects are the most important epidemiological factors for plant virus disease spread, with >75% of viruses being dependent on insects for transmission to new hosts. The black-faced leafhopper (Graminella nigrifrons Forbes) transmits two viruses that use different strategies for transmission: Maize chlorotic dwarf virus (MCDV) which is semi-persistently transmitted and Maize fine streak virus (MFSV) which is persistently and propagatively transmitted. To date, little is known regarding the molecular and cellular mechanisms in insects that regulate the process and efficiency of transmission, or how these mechanisms differ based on virus transmission strategy.
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Photoemission mechanism of water-soluble silver nanoclusters: ligand-to-metal-metal charge transfer vs strong coupling between surface plasmon and emitters.
J. Am. Chem. Soc.
PUBLISHED: 01-27-2014
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Using carboxylate-protected silver nanoclusters (Ag-carboxylate NCs) as a model, we separately investigated the contribution of the ligand shell and the metal core to understand the nature of photoluminescence of Ag NCs. A new Ag(0)NCs@Ag(I)-carboxylate complex core-shell structural model has been proposed. The emission from the Ag-carboxylate NCs could be attributed to ligand-to-metal-metal charge transfer from Ag(I)-carboxylate complexes (the oxygen atom in the carboxylate ligands to the Ag(I) ions) to the Ag atoms and subsequent radiative relaxation. Additionally, we found that the emission wavelength of the Ag NCs depends on the excitation wavelength implying a strong coupling between surface plasmon and emitter in Ag NCs. The strong coupling between the surface plasmon and the emitter determines the quantum yield and lifetime. The emission mechanism of Ag NCs and its relation to the organic templates and metal cores were clearly clarified. The results should stimulate additional experimental and theoretical research on the molecular-level design of luminescent metal probes for optoelectronics and other applications.
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Increased incidence of osteoarthritis of knee joint after ACL reconstruction with bone-patellar tendon-bone autografts than hamstring autografts: a meta-analysis of 1,443 patients at a minimum of 5 years.
Eur J Orthop Surg Traumatol
PUBLISHED: 01-05-2014
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The objective of this study was to evaluate the effectiveness of BPTB autografts versus HT autografts at a minimum of 5 years after anterior cruciate ligament (ACL) reconstruction.
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Drosophila USP5 controls the activation of apoptosis and the Jun N-terminal kinase pathway during eye development.
PLoS ONE
PUBLISHED: 01-01-2014
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The Jun N-terminal kinase pathway plays an important role in inducing programmed cell death (apoptosis) and is activated in a variety of contexts. The deubiquitinating enzymes (DUBs) are proteases regulating the protein stability by ubiquitin-proteasome system. Here, for the first time, we report the phenotypes observed during eye development that are induced by deleting Drosophila USP5 gene, which encodes one of the USP subfamily of DUBs. usp5 mutants displayed defects in photoreceptor differentiation. Using genetic epistasis analysis and molecular markers, we show that most of these phenotypes are caused by the activation of apoptosis and JNK pathway. These data may provide a mechanistic model for understanding the mammalian usp5 gene.
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[Isolation and expression profiling of transformer 2 gene in Aedes aegypti].
Nan Fang Yi Ke Da Xue Xue Bao
PUBLISHED: 11-26-2013
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To isolate, identify and analyze the sex-determining gene Transformer 2 (Aaetra2) of the major vector mosquito Aedes aegypti.
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Porphyrin-POSS molecular hybrids.
Chemistry
PUBLISHED: 11-01-2013
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Porphyrin-POSS hybrid: Porphyrin-POSS molecular hybrid composites (see scheme; POSS = polyhedral oligomeric silsesquioxanes) were synthesized and structurally characterized, allowing the realization of truly homogenous dispersion of basic functional building blocks between organic and inorganic components at the molecular level. These materials allow the optimization of aggregation/association behavior and thus the functional optical properties of the porphyrinato zinc compounds.
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Azacrown[N,S,O]-modified porphyrin sensor for detection of Ag+, Pb2+, and Cu2+.
Photochem. Photobiol. Sci.
PUBLISHED: 09-24-2013
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One new azacrown[N,S,O]-modified metal-free porphyrin derivative, H2Por-azacrown (1), with the central tetrapyrrole moiety as signaling fluorophore and/or metal ion receptor has been designed, synthesized, and characterized. Addition of Ag(+) into this novel metal-free porphyrin compound induces a fluorescence ON-OFF process, while adding Pb(2+) leads to absorption/emission-ratiometric signals. Quite interestingly, blue-shift of the Soret band, ratiometric change of Q bands, and dual-signal changes (absorption ratio and fluorescence ON-OFF) associated with the Cu(2+) displacement from the 1-Pb(2+) system were observed upon addition of Cu(2+). These results render this H2Por-azacrown compound a porphyrin-based multi-responsive optical sensor towards Ag(+), Pb(2+), and in particular Cu(2+) with dual-mode detecting potential.
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N,N-di(2-pyridylmethyl)amino-modified porphyrinato zinc complexes. The "ON-OFF" fluorescence sensor for Fe3+.
Spectrochim Acta A Mol Biomol Spectrosc
PUBLISHED: 04-19-2013
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Two porphyrinato-zinc derivatives modified with two and four N,N-di(2-pyridylmethyl)amino groups, namely Zn-Porphyrin-2-DPA (1) and Zn-Porphyrin-4-DPA (2), have been designed, synthesized, and characterized. Systemic studies over a series of metal ions reveal that binding with Fe(3+) for the former compound induces the decrease of fluorescence emission intensity by 37.2%, while for the latter one results in a more remarkable decrease in the fluorescence emission intensity by 90.3%, rendering compound 2 the first example of DPA-modified porphyrin fluorescence ON-OFF sensor for Fe(3+).
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Boron-phenylpyrrin dyes: facile synthesis, structure, and pH-sensitive properties.
Chemistry
PUBLISHED: 04-04-2013
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Boron-phenylpyrrin dyes: In the presence of BF3?OEt2, 4-(diethylamino)salicylaldehyde reacts with substituted pyrroles to give boron-phenylpyrrin dyes, which contain a central boron-containing seven-membered ring. Upon protonation in acidic solution, the complexes, with a large Stokes shift, exhibit a color change and a unique red shift in both the electronic absorption and fluorescence emission spectra (see picture), thus rendering them new analogues of boron-dipyrrin dyes that can be used as pH sensors.
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Silicon-mediated tomato resistance against Ralstonia solanacearum is associated with modification of soil microbial community structure and activity.
Biol Trace Elem Res
PUBLISHED: 01-14-2013
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Bacterial wilt caused by Ralstonia solanacearum is a serious soil-borne disease of Solanaceae crops. In this study, the soil microbial effects of silicon-induced tomato resistance against R. solanacearum were investigated through pot experiment. The results showed that exogenous 2.0 mM Si treatment reduced the disease index of bacterial wilt by 19.18 % to 52.7 % compared with non-Si-treated plants. The uptake of Si was significantly increased in the Si-treated tomato plants, where the Si content was higher in the roots than that in the shoots. R. solanacearum inoculation resulted in a significant increase of soil urease activity and reduction of soil sucrase activity, but had no effects on soil acid phosphatase activity. Si supply significantly increased soil urease and soil acid phosphatase activity under pathogen-inoculated conditions. Compared with the non-inoculated treatment, R. solanacearum infection significantly reduced the amount of soil bacteria and actinomycetes by 52.5 % and 16.5 %, respectively, but increased the ratio of soil fungi/soil bacteria by 93.6 %. After R. solanacearum inoculation, Si amendments significantly increased the amount of soil bacteria and actinomycetes and reduced soil fungi/soil bacteria ratio by 53.6 %. The results suggested that Si amendment is an effective approach to control R. solanacearum. Moreover, Si-mediated resistance in tomato against R. solanacearum is associated with the changes of soil microorganism amount and soil enzyme activity.
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Ac-cel, a novel antioxidant, protects against hydrogen peroxide-induced injury in PC12 cells via attenuation of mitochondrial dysfunction.
J. Mol. Neurosci.
PUBLISHED: 01-07-2013
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Oxidative stress has been implicated in pathophysiology of many neurodegenerative diseases (ND) and increased oxidative stress is closely associated with mitochondrial dysfunction. As a result, looking for potent antioxidants, especially those targeting mitochondria, has become an attractive strategy in ND therapy. In this study, we explored protective effects and potential mechanism of Ac-cel, a novel compound, against hydrogen peroxide (H(2)O(2))-induced injury in PC12 cells. Pretreatment of PC12 cells with Ac-cel prior to 24 h of H(2)O(2) exposure markedly attenuated cytotoxicity induced by H(2)O(2) as evidenced by morphological changes and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Ac-cel also exhibited potent antiapoptotic effect demonstrated by results of annexin V and PI staining. The above beneficial effects of Ac-cel were accompanied by improved mitochondrial function, reduced caspase-3 cleavage as well as upregulated ratio of Bcl-2/Bax protein expression. Moreover, Ac-cel pretreatment markedly reversed intracellular reactive oxygen species (ROS) accumulation following 30 min of H(2)O(2) exposure in PC12 cells. Further, subcellular investigation indicated that Ac-cel significantly reduced production of mitochondrial ROS in isolated rat cortical mitochondria. Taken together, the present study, for the first time, reports that Ac-cel pretreatment inhibits H(2)O(2)-stimulated early accumulation of intracellular ROS possibly via reducing mitochondrial ROS production directly and leads to subsequent preservation of mitochondrial function. These results indicate that Ac-cel is a potential drug candidate for treatment of oxidative stress-associated ND.
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Rational design and synthesis for versatile FRET ratiometric sensor for Hg2+ and Fe2+: a flexible 8-hydroxyquinoline benzoate linked Bodipy-porphyrin dyad.
Org. Lett.
PUBLISHED: 10-10-2011
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A flexible 8-hydroxyquinoline benzoate linked Bodipy-porphyrin dyad has been designed, synthesized, and characterized. Binding of this dyad with Hg(2+)/Fe(2+) induced just the opposite (promoting/restraining) influence on energy transfer from the Bodipy donor to the porphyrin acceptor, resulting in a remarkably different ratio change of two signal emissions, endowing this dyad as the first Bodipy-porphyrin-based versatile fluorescence resonance energy transfer (FRET) ratiometric sensor for Hg(2+) and Fe(2+) ions, respectively.
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Dissociative double ionization of 1-bromo-2-chloroethane irradiated by an intense femtosecond laser field.
J Chem Phys
PUBLISHED: 08-17-2011
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The dissociative double ionization and multi-photon ionization of 1-bromo-2-chloroethane (BCE) irradiated by the 800 nm femtosecond laser field have been investigated by dc-slice imaging technology. The charged parent ion ratio [BCE(2+)]/[BCE(+)] was measured, and the corresponding ionization process including non-sequential double ionization and sequential double ionization was analyzed. The sliced images of different photo-dissociated ions were detected, and the corresponding kinetic energy release (KER) distributions were calculated and extracted. Furthermore, the dissociative double ionization channels, attributed to the cleavage of the C-C, C-Br, and C-Cl bonds by the Coulombic repulsive forces, were discussed, and the revised equilibrium distance R(e)*, the energy ratio E(exp)/E(coul), and the value a=?(R(e)*)/(E(exp)/E(coul)) were calculated.
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8-Hydroxyquinoline-substituted boron-dipyrromethene compounds: synthesis, structure, and OFF-ON-OFF type of pH-sensing properties.
J. Org. Chem.
PUBLISHED: 04-15-2011
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A series of four novel 8-hydroxyquinoline-substituted boron-dipyrromethene derivatives, namely 4,4-difluoro-8-(5-(8-hydroxyquinoline))-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (1), 4,4-difluoro-8-(5-(8-hydroxyquinoline))-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (2), 4,4-difluoro-8-(5-azastyryl-(8-hydroxyquinoline))-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (3), and 4,4-difluoro-8-(5-azastyryl-(8-hydroxyquinoline))-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (4), have been synthesized and characterized by a series of spectroscopic methods. The molecular structures of 1 and 2 have been determined by single-crystal X-ray diffraction analyses. The two methyl substituents attached at C-1 and C-7 positions of boron-dipyrromethene (Bodipy) in compound 2 was revealed to prevent the free rotation of the 8-hydroxyquinoline (8-HQ) moiety, resulting in an almost vertical 8-HQ-Bodipy configuration of this compound. This is obviously different from those for 1 with the dihedral angle between 8-hydroxyquinoline and Bodipy moieties of 65.44 and 66.79° due to the lack of methyl substituents in the latter compound. The intense fluorescence from the Bodipy subunit of these compounds was revealed to gradually get diminished along with either decreasing or increasing the pH value under acidic and basic conditions, respectively, in particular for 1, 2, and 4 because of the photoinduced intramolecular electron transfer from excited Bodipy moiety to 8-HQ unit and just an opposite process. This renders these compounds the first OFF-ON-OFF type of pH-dependent fluorescent sensors. Nevertheless, both the intrinsic fluorescence of these compounds and their fluorescent quenching properties along with the change in the pH value have been found to depend on the steric configuration as well as the linking group between 8-hydroxyquinoline and Bodipy moieties, revealing the effect of molecular structure on their fluorescence properties.
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Modulation of the spectroscopic property of Bodipy derivates through tuning the molecular configuration.
Photochem. Photobiol. Sci.
PUBLISHED: 03-08-2011
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A series of six Bodipy derivatives, namely 4,4-difluoro-8-(4-amidophenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (1), 4,4-difluoro-8-(4-methylphenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (2), 4,4-difluoro-8-(4-nitrylphenyl)-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (3), 4,4-difluoro-8-(4-amidophenyl)-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (4), 4,4-difluoro-8-(4-methylphenyl)-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (5), and 4,4-difluoro-8-(4-nitrylphenyl)-3,5-dimethyl-4-bora-3a,4a-diaza-s-indacene (6) were structurally characterized by single crystal X-ray diffraction analysis. Two methyl substituents attached at C-1 and C-7 positions of boron-dipyrromethene (Bodipy) moiety in compounds 1-3 were revealed to prevent the free rotation of the benzene moiety, resulting in a molecular configuration with an almost orthogonal dihedral angle between the Bodipy and benzene moieties with the dihedral angle in the range of 81.14-88.56°. This is obviously different from that for 4-6 with a free-rotating benzene moiety relative to the Bodipy core due to the lack of two methyl substituents in the latter series of compounds, leading to an enhanced interaction between the Bodipy and benzene moieties for 4-6 in comparison with 1-3. The resulting larger HOMO-LUMO gap for 1-3 than 4-6 results in a blue-shifted absorption band for 1-3 relative to that for 4-6. Comparative studies over their fluorescence properties also disclose the blue-shifted fluorescence emission band and corresponding higher fluorescence quantum yield for 1-3 relative to those of 4-6, revealing the effect of molecular configuration on the spectroscopic properties of Bodipy derivatives. Comparison of the redox behaviors of these two series of Bodipy compounds provides additional support for this point. In addition, the electron-donating/withdrawing property of the para substituent of the benzene moiety was shown to exhibit a slight influence on the electronic absorption and fluorescence emission properties of the Bodipy compounds.
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4-(4,4-Difluoro-1,3,5,7-tetra-methyl-3a-aza-4a-azonia-4-borata-s-indacen-8-yl)benzonitrile.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 02-23-2011
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The title compound, C(20)H(18)BF(2)N(3), contains one C(9)BN(2) (Bodipy) framework and one cyano-benzyl group. The Bodipy framework is essentially planar with a maximum deviation of 0.041?(2)?Å. The introduction of two methyl groups at positions 1 and 7 of s-indacene in the Bodipy unit results in almost orthogonal configuration between the mean plane of the Bodipy unit and the cyano-benzyl group [dihedral angle = 89.78?(4)°].
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Three-dimensional inverted photonic grating with engineerable refractive indices for broadband antireflection of terahertz waves.
Opt Lett
PUBLISHED: 10-05-2010
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Reduction of reflection is of great importance in optical spectroscopy to reduce interference and increase throughput. Here we demonstrate a three-dimensional inverted photonic grating device design using only one material-silicon. Enhanced transmission compared to planar silicon wafers is observed from 0.2 THz to over 7.3 THz for a device with a 15 µm period, which covers most of the terahertz band, and its relative 3 dB bandwidth (?f/f(c)) is a noteworthy 116.3%. Moreover, the device is polarization independent and can perform up to a large incident angle.
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Heterobimetallic porphyrin-based single-chain magnet constructed from manganese(III)-porphyrin and trans-dicyanobis(acetylacetonato) ruthenate(III) containing co-crystallized bulk anions and cations.
Chem. Commun. (Camb.)
PUBLISHED: 03-24-2010
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Two cyanide-bridged alternated 1 : 1 Ru(III)/Mn(III) complexes structurally characterized as single-chain containing co-crystallized bulk anions and cations have been successfully assembled from [Mn(TPP)(H(2)O)(2)](+) and [Ru(acac)(2)(CN)(2)](-) blocks. Systematic investigation of their magnetic properties reveals typical single-chain magnet (SCM) behaviors for both of them.
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Hydrogen-bond directed cyanide-bridged molecular magnets derived from polycyanidemetalates and Schiff base manganese(III) compounds: synthesis, structures, and magnetic properties.
Inorg Chem
PUBLISHED: 10-28-2009
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A series of six new cyanide-bridged heterometallic complexes including two tetranuclear T-like Fe(III)Mn(III)(3) compounds, {[Mn(L(1))(H(2)O)](3)[Fe(CN)(5)(1-CH(3)im)]}ClO(4) x 1.5 H(2)O (1) and {[Mn(L(2))(H(2)O)](3)[Fe(CN)(5)(1-CH(3)im)]}ClO(4) x 3 H(2)O (2); two heptanuclear cage-shaped M(III)Mn(III)(6) (M = Fe, Cr) compounds, {[Mn(L(2))(H(2)O)](6)[Fe(CN)(6)]}[Fe(CN)(6)] x 6 CH(3)OH (3) and {[Mn(L(2))(H(2)O)](6)[Cr(CN)(6)]}[Cr(CN)(6)] x 6 CH(3)OH (4); and two two-dimensional M-Mn(III) networks, {[H(3)O][Mn(L(1))](2)[Fe(CN)(6)]} x 2 DMF (5) and {K[Mn(L(1))](2)[Cr(CN)(6)]} x 1.5 CH(3)CN x CH(3)OH (6) (L(1) = N,N-ethylene-bis(3-methoxysalicylideneiminate, L(2) = N,N-ethylene-bis(3-ethoxysalicylideneiminate) have been successfully assembled from three polycyanidemetalates containing five or six cyanide groups and two manganese(III) building blocks containing bicompartmental Schiff base ligands. The cyanide-bridged polynuclear complexes are self-complementary through a coordinated aqua ligand from one complex and the free O(4) compartment from the neighboring complex, giving supramolecular one-dimensional ladders and three-dimensional networks for 1 and 2 and for 3 and 4, respectively. Investigation over magnetic susceptibilities of the six complexes reveals the overall ferromagnetic interactions for complexes 1, 2, 3, and 5 and antiferromagnetic interaction for 4 and 6. Compounds 1-4 show some characteristics of metamagnet behavior at low temperatures due to the relatively strong intermolecular hydrogen-bonding interaction. The two complexes with two-dimensional structure exhibit three-dimensional antiferromagnetic ordering with typical metamagnetic behavior below 8.4 K for 5 and 11.5 K for 6, respectively. The present result appears to add new members to the very few examples of polynuclear clusters exhibiting 3D magnetic ordering relying on intermolecular interactions, to the best of our knowledge, which will be helpful for providing valuable information for the understanding and application of intermolecular hydrogen-bonding interactions in the molecular magnetic materials.
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Synthesis, structure, and magnetic properties of cyanide-bridged low-dimensional heterometallic Fe(III)-Mn(II) complexes.
Dalton Trans
PUBLISHED: 09-02-2009
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With trans-dicyanideiron(III) precursor K[Fe(salen)(CN)(2)] x CH(3)OH (1) (H(2)salen = N,N-bis(salicyl)ethylenediamine) as a building block, four new cyanide-bridged heterometallic Fe(III)-Mn(II) complexes {[Fe(salen)(CN)(2)](2)[Mn(bipy)(2)]} x CH(3)OH x 2 H(2)O (2), {[Fe(salen)(CN)(2)](2)[Mn(phen)(2)]} x CH(3)OH (3), and {[Fe(salen)(CN)(2)][Mn(L)]}ClO(4) x CH(3)OH [L = L(a) (4) and L(b) (5)] have been successfully assembled. Single X-ray diffraction analyses reveals the trinuclear Fe(III)(2)Mn(II) nature of complexes 2 and 3 comprised of one [Mn(bipy)(2)](2+)/[Mn(phen)(2)](2+) and two [Fe(salen)(CN)(2)](-) units, and the one-dimensional cyanide-bridged cationic polymeric single chain nature of complexes 4 and 5 consisting of alternating units of [Mn(L)](2+) (L = L(a) and L(b)) and [Fe(salen)(CN)(2)](-) with free ClO(4)(-) as balanced anions. Investigations into the magnetic properties of these four heterometallic cyanide-bridged Fe(III)-Mn(II) complexes reveals the overall antiferromagnetic interaction between neighbouring Fe(III) and Mn(II) ions through the bridging cyanide group. On the basis of the Hamiltonian H = -2JS(Mn)(S(Fe(1)) + S(Fe(2))), the magnetic simulation for the trimeric complexes 2 and 3 gives the magnetic coupling constant 2J(MnFe) = -2.68(4) cm(-1) for 2 and 2J(MnFe) = -2.46(8) cm(-1) for 3, respectively. A best-fit to the magnetic susceptibilities of 4 and 5 based on the one-dimensional alternating chain model leads to the magnetic coupling constants 2J(1) = -6.50(2) and 2J(2) = -1.57(1) cm(-1) for 4 and 2J(1) = -5.35(2) and 2J(2) = -0.93(1) cm(-1) for 5.
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Rational design and assembly of a new series of cyanide-bridged Fe(III)-Mn(II) one-dimensional single chain complexes: synthesis, crystal structures, and magnetic properties.
Inorg Chem
PUBLISHED: 05-16-2009
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Two mononuclear seven-coordinated macrocycle manganese(II) compounds and three dicyanide-containing precursors have been employed as building blocks to assemble cyanide-bridged heterobimetallic complexes, resulting in five new cyanide-bridged single chain complexes {[Mn(L(1))][Fe(bpb)(CN)(2)]}ClO(4) x 0.5 H(2)O (2), {[Mn(L(2))][Fe(bpb)(CN)(2)]}ClO(4) x 0.5 H(2)O (3), {[Mn(L(1))][Fe(bpClb)(CN)(2)]}ClO(4) x H(2)O (4), {[Mn(L(2))][Fe(bpClb)(CN)(2)]}ClO(4) x 0.5 H(2)O (5), and {[Mn(L(1))][Fe(bpdBrb)(CN)(2)]}ClO(4) x H(2)O (6). Single X-ray diffraction analysis reveals their one-dimensional (1D) single cyanide-bridged cationic polymeric chain structure consisting of alternating units of [Mn(L)](2+) (L = L(1) or L(2)) and [Fe(L)(CN)(2)](-) (L = bpb(2-), bpClb(2-) or bpdBrb(2-)) with free ClO(4)(-) as balanced anion. Similar to the mononuclear macrocyclic manganese(II) precursor {[Mn(L(2))(H(2)O)Cl]ClO(4)}.CH(3)OH (1), the coordination geometry of manganese(II) ion in all the 1D complexes is a slightly distorted pentagonal-bipyrimidal with two cyanide nitrogen atoms at the trans positions and N(5) or N(3)O(2) coordinating mode at the equatorial plane from ligand L(1) or L(2). Investigation of the magnetic properties of these five 1D single chain cyanide-bridged Fe(III)-Mn(II) complexes reveals the antiferromagnetic magnetic coupling between neighboring Fe(III) and Mn(II) ions through the bridging cyanide group. A best-fit to the magnetic susceptibilities of these complexes based on the 1D alternating chain model leads to the magnetic coupling constants J(1) = -1.16(2) and J(2) = -0.10(3) cm(-1) for 2, J(1) = -3.10(1) and J(2) = -0.25(1) cm(-1) for 3, J(1) = -1.10(1) and J(2) = -0.139(8) cm(-1) for 4, J(1) = -1.99(6) and J(2) = -0.57(1) cm(-1) for 5, and J(1) = -1.23(1) and J(2) = -0.13(5) cm(-1) for 6, respectively. This work will provide valuable information for the rational design and synthesis of low-dimensional, in particular, single chain, cyanide-bridged magnetic complexes.
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Transcriptome of the plant virus vector Graminella nigrifrons, and the molecular interactions of maize fine streak rhabdovirus transmission.
PLoS ONE
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Leafhoppers (HEmiptera: Cicadellidae) are plant-phloem feeders that are known for their ability to vector plant pathogens. The black-faced leafhopper (Graminella nigrifrons) has been identified as the only known vector for the Maize fine streak virus (MFSV), an emerging plant pathogen in the Rhabdoviridae. Within G. nigrifrons populations, individuals can be experimentally separated into three classes based on their capacity for viral transmission: transmitters, acquirers and non-acquirers. Understanding the molecular interactions between vector and virus can reveal important insights in virus immune defense and vector transmission.
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Porphyrin-based multi-signal chemosensors for Pb2+ and Cu2+.
Org. Biomol. Chem.
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Two metal-free tetra(aryl)porphyrin derivatives modified by one and four N,N-bis(2-pyridylmethyl)amino group(s), namely porphyrin-1-DPA (1) and porphyrin-4-DPA (2) respectively, have been designed, synthesized, and characterized. Binding with Pb(2+) induces a significant change in their solution color and in the ratio of two absorption/fluorescence signal peaks, rendering them the first example of porphyrin-based triple-signal optical sensors for Pb(2+). Their dual-mode Cu(2+)-selective sensing properties via either the porphyrin fluorescence ON-OFF mechanism or metal displacement from the 1-Pb(2+) complex that results in a triple-signal change clearly reveals their potential application as excellent and versatile sensors.
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