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Observation of the asymmetric Bessel beams with arbitrary orientation using a digital micromirror device.
Opt Express
PUBLISHED: 11-18-2014
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Recently, V. V. Kotlyar et al. [Opt. Lett.39, 2395 (2014)] have theoretically proposed a novel kind of three-parameter diffraction-free beam with a crescent profile, namely, the asymmetric Bessel (aB) beam. The asymmetry degree of such nonparaxial modes was shown to depend on a nonnegative real parameter c. We present a more generalized asymmetric Bessel mode in which the parameter c is a complex constant. This parameter controls not only the asymmetry degree of the mode but also the orientation of the optical crescent, and affects the energy distribution and orbital angular momentum (OAM) of the beam. As a proof of concept, the high-quality generation of asymmetric Bessel-Gauss beams was demonstrated with the super-pixel method using a digital micromirror device (DMD). We investigated the near-field properties as well as the far field features of such beams, and the experimental observations were in good agreement with the theoretical predictions. Additionally, we provided an effective way to control the beam's asymmetry and orientation, which may find potential applications in light-sheet microscopy and optical manipulation.
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Widely-tunable, passively Q-switched erbium-doped fiber laser with few-layer MoS2 saturable absorber.
Opt Express
PUBLISHED: 11-18-2014
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We propose and demonstrate a MoS2-based passively Q-switched Er-doped fiber laser with a wide tuning range of 1519.6-1567.7 nm. The few-layer MoS2 nano-platelets are prepared by the liquid-phase exfoliation method, and are then made into polymer-composite film to construct the fiber-compatible MoS2 saturable absorber (SA). It is measured at 1560 nm wavelength, that such MoS2 SA has the modulation depth of ?2% and the saturable optical intensity of ?10 MW/cm2. By further inserting the filmy MoS2-SA into an Er-doped fiber laser, stable Q-switching operation with a 48.1 nm continuous tuning from S- to C-waveband is successfully achieved. The shortest pulse duration and the maximum pulse energy are 3.3 ?s and 160 nJ, respectively. The repetition rate and the pulse duration under different operation conditions have been also characterized. To the best of our knowledge, it is the first demonstration of MoS2 Q-switched, widely-tunable fiber laser.
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Rational modifications on champion porphyrin dye using different electron-withdrawing moieties toward high performance dye-sensitized solar cells.
Phys Chem Chem Phys
PUBLISHED: 10-21-2014
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Ten porphyrin sensitizers with different electron-withdrawing groups derived from the best sensitizer were investigated by means of the density functional theory (DFT) and time-dependent DFT calculations. To this end, major factors affecting the performance of the cell, including light harvesting, electron injection, dye regeneration, and conduction band energy shift are taken into consideration. Especially, the calculated distance (r) from the electron recapture center to the semiconductor surface is used to probe the charge recombination process. In addition, considering the complexity of the porphyrin sensitizers' absorption, the maximum short circuit current density (J) is determined for investigating the light harvesting ability quantitatively. We find that when compared to with 2,1,3-benzothiadiazole, with naphtho[1,2-c:5,6-c]bis[1,2,5]thiadiazole shows better performance due to both larger J and r, and with diketopyrrolopyrrole could also be a promising candidate due to the much larger J and comparable r.
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Two carboxyethyltin functionalized polyoxometalates for assembly on carbon nanotubes as efficient counter electrode materials in dye-sensitized solar cells.
Chem. Commun. (Camb.)
PUBLISHED: 10-16-2014
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Two novel open-chain carboxyethyltin decorated sandwich-type germanotungstates have been successfully synthesized. They could markedly increase the electrocatalytic activity of single-walled carbon nanotubes toward triiodide reduction when assembled into composite electrodes, which have shown a conversion efficiency of 6.32% that is comparable to that of Pt electrodes (6.29%) when used as counter electrodes in dye-sensitized solar cells.
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A designed bithiopheneimide-based conjugated polymer for organic photovoltaic with ultrafast charge transfer at donor/PC71BM interface: theoretical study and characterization.
Phys Chem Chem Phys
PUBLISHED: 09-24-2014
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In the current work, a series of bithiopheneimide (BTI)-based D-A copolymers were investigated based on the reported PDTSBTI (1) to screen excellent molecules toward organic photovoltaic (OPV) donor materials. It is found that the PCE based on the proposed derivative 4, where the silicon atom is replaced with vinyl and cyano groups on the DTS unit, shows a 70 percent improvement by Scharber diagrams compared with its prototype 1. Then, the charge transfer dynamics of 1/PC71BM and 4/PC71BM were investigated, including the intermolecular charge transfer (inter-CT) and recombination (inter-CR) rates. The theoretical data demonstrate that the ratio kinter-CT/kinter-CR of 4/PC71BM heterojunction is about 1 × 10(5) times higher than that of 1/PC71BM. These results clearly reveal that the designed donor molecule 4 will be a promising candidate for high-performance OPV device. We expect that this work from electron processing at the D/A interface may provide a theoretical guideline for further optimization and design of organic copolymer donor materials.
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Assembly of Fe-substituted Dawson-type nanoscale selenotungstate clusters with photocatalytic H2 evolution activity.
Chem. Commun. (Camb.)
PUBLISHED: 09-18-2014
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Two Fe-substituted Dawson-type nanoscale selenotungstate clusters, {Fe6Se6W34} and {Fe10Se8W62} involving {?-Se2W14} and {?-Se2W14} building blocks, have been isolated, which exhibit photocatalytic H2 evolution activity. Their electrochemical behaviours and magnetic properties were also investigated.
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An ultrastable {Ag55Mo6} nanocluster with a Ag-centered multishell structure.
Chem. Commun. (Camb.)
PUBLISHED: 08-27-2014
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An ultrastable [Ag55(MoO4)6](43+) ({Ag55Mo6} for short) nanocluster with a Ag-centered multishell structure in compound [Ag55(MoO4)6(C?C(t)Bu)24(CH3COO)18](OAc)·2H2O (1) has been obtained. The ultrastability of 1 was demonstrated by Mulliken population analysis. In addition, the potential wide gap semiconductor property and electrochemical properties of 1 were investigated.
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pH-controlled and sulfite anion-directed assembly of a family of cerium(III)-containing polyoxotungstates clusters.
Inorg Chem
PUBLISHED: 08-25-2014
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A versatile one-pot strategy was employed to synthesize five cerium(III)-containing polyoxotungstate nanoclusters through pH-controlled and sulfite anion-directed assembly: [C2H8N]3Na7[Ce2(H2O)6W22O72(OH)4]·20H2O (1) at pH 5.0; [C2H8N]8Na16[Ce4(H2O)12W44O144(OH)12]·23H2O (2) at pH 4.5; [C2H8N]2Na4Ce2[Ce2(H2O)10W28O92(OH)2]·27H2O (3) at pH 2.8-3.3; [C2H8N]2Na7[{?-SW7O28}{Ce2(H2O)6}(W3O6){?-SW9O32}{?-SW9O31(OH)}]·18H2O (4) at pH 2.5; [C2H8N]2Na18[Ce2(H2O)9W36O110(OH)12]2·30H2O (5) at pH 1.5. These compounds were characterized by single-crystal X-ray structure analysis, IR spectroscopy, thermogravimetric (TG) analysis, X-ray photoelectron spectroscopy (XPS), and electrospray ionization mass spectrometry (ESI-MS). Moreover, their electrochemical properties were investigated. Single-crystal X-ray structure analysis revealed that 1 and 2 were di- and tetra-cerium(III)-bridged polyoxotungstates, constructed from two different types of lacunary {W11} units. 3 composed of the well-known cerium(III)-stabilized {W28} unit and organic amine-sodium-cerium cations, was isolated in the pH range 2.8-3.3. In this reaction system, the SO3(2-) anion acted as a heteroanion template at a lower pH 2.5. 4 was isolated by the combination of cerium(III) centers and SO3(2-) heteroanion template, which is the first lanthanide-containing polyoxotungstates with sulfur heteroatoms, and the 4f metal cerium(III) centers in 4 both have eight-coordinated modes and the SO3(2-) heteroanion templates display ?7 and ?9 coordination modes. At a much lower pH 1.5, the polyanion of 5 was obtained, two triangular-shaped {W36} subunits were bridged by the cerium(III) ions, resulting in the largest lanthanide-containing iso-polyoxotungstates known to date.
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Expressions of heparanase and upstream stimulatory factor in hepatocellular carcinoma.
Eur. J. Med. Res.
PUBLISHED: 08-23-2014
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The expression of heparanase (HPSE) was associated with postoperative metastatic recurrence in patients with hepatocellular carcinoma (HCC). The six E-box binding sites in the core promoter of the HPSE gene suggested that transcription factors of E-box such as upstream stimulatory factor (USF) might regulate the transcription of the HPSE gene. The aim of our study is to measure the levels of HPSE and USF expression and investigate the relationship between USF expression and clinicopathological parameters in patients with HCC.
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How does hybrid bridging core modification robust the nonlinear optical properties in donor-?-acceptor configuration? A case study of dinitrophenol derivatives.
J Comput Chem
PUBLISHED: 08-17-2014
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This study spotlights the fundamental insights about the structure and static first hyperpolarizability (?) of a series of 2,4-dinitrophenol derivatives (1-5), which are designed by novel bridging core modifications. The central bridging core modifications show noteworthy effects to modulate the optical and nonlinear optical properties in these derivatives. The derivative systems show significantly large amplitudes of first hyperpolarizability as compared to parent system 1, which are 4, 46, 66, and 90% larger for systems 2, 3, 4, and 5, respectively, at Moller-Plesset (MP2)/6-31G* level of theory. The static first hyperpolarizability and frequency dependent coupled-perturbed Kohn-Sham first hyperpolarizability are calculated by means of MP2 and density functional theory methods and compared with respective experimental values wherever possible. Using two-level model with full-set of parameters dependence of transition energy (??), transition dipole moment (?(0) ) as well as change in dipole moment from ground to excited state (??), the origin of increase in ? amplitudes is traced from the change in dipole moment from ground to excited state. The causes of change in dipole moments are further discovered through sum of Mulliken atomic charges and intermolecular charge transfer spotted in frontier molecular orbitals analysis. Additionally, analysis of conformational isomers and UV-Visible spectra has been also performed for all designed derivatives. Thus, our present investigation provides novel and explanatory insights on the chemical nature and origin of intrinsic nonlinear optical (NLO) properties of 2,4-dinitrophenol derivatives. © 2014 Wiley Periodicals, Inc.
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Stepwise modulation of the electron-donating strength of ancillary ligands: understanding the AIE mechanism of cationic iridium(III) complexes.
Chem. Commun. (Camb.)
PUBLISHED: 08-06-2014
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The AIE mechanism for cationic Ir(III) complexes with triazole-pyridine ligands has been determined by the combination of an experimental and a computational study. Larger structural relaxation and weak emissive excited-state intraligand charge transfer (ILCT) characters are responsible for the non-emission in solution, whereas the non-radiative processes are efficiently restricted in the solid state, enhancing the emission.
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Calibration of optical tweezers based on an autoregressive model.
Opt Express
PUBLISHED: 08-05-2014
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The power spectrum density (PSD) has long been explored for calibrating optical tweezers stiffness. Fast Fourier Transform (FFT) based spectral estimator is typically used. This approach requires a relatively longer data acquisition time to achieve adequate spectral resolution. In this paper, an autoregressive (AR) model is proposed to obtain the Spectrum Density using a limited number of samples. According to our method, the arithmetic model has been established with burg arithmetic, and the final prediction error criterion has been used to select the most appropriate order of the AR model, the power spectrum density has been estimated based the AR model. Then, the optical tweezers stiffness has been determined with the simple calculation from the power spectrum. Since only a small number of samples are used, the data acquisition time is significantly reduced and real-time stiffness calibration becomes feasible. To test this calibration method, we study the variation of the trap stiffness as a function of the parameters of the data length and the trapping depth. Both of the simulation and experiment results have showed that the presented method returns precise results and outperforms the conventional FFT method when using a limited number of samples.
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Pyrrole-phenylboronic acid: A novel monomer for dopamine recognition and detection based on imprinted electrochemical sensor.
Biosens Bioelectron
PUBLISHED: 08-02-2014
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A molecular imprinting polymer (MIP) based electrochemical sensor was successfully prepared for dopamine (DA) recognition and detection using pyrrole-phenylboronic acid (py-PBA) as a novel electropolymerized monomer. py-PBA could form cyclic boronic ester bond with DA, thus endowing a double recognition capacity of the sensor to DA in the combination of the imprinted effect of MIP. Compared with the sensor prepared using pyrrole or phenylboronic acid as electropolymerized monomer, the present sensor exhibited a remarkable high imprinted factor to DA. The influence factors including pH value, the mole ratio between monomer and template molecule, electropolymerization scan rate, and scan cycles of electropolymerization process were investigated and optimized. Under the optimal conditions, the sensor could recognize DA from its analogs and monosaccharides. A linear ranging from 5.0×10(-8) to 1.0×10(-5)mol/L for the detection of DA was obtained with a detection limit of 3.3×10(-8)mol/L (S/N=3). The sensor has been applied to analyze DA in injection samples with satisfactory results.
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2D Cd(II)-lanthanide(III) heterometallic-organic frameworks based on metalloligands for tunable luminescence and highly selective, sensitive, and recyclable detection of nitrobenzene.
Inorg Chem
PUBLISHED: 07-23-2014
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In this work, five novel 2D isostructural Cd(II)-lanthanide(III) heterometallic-organic frameworks [CdCl(L)Eu(x)Tb(y)(H2O)(DMA)](NO3)·3DMA (IFMC-36-Eu(x)Tb(y): x = 1, y = 0, IFMC-36-Eu; x = 0.6, y = 0.4, IFMC-36-Eu(0.6)Tb(0.4); x = 0.5, y = 0.5, IFMC-36-Eu(0.5)Tb(0.5); x = 0.4, y = 0.6, IFMC-36-Eu(0.4)Tb(0.6); x = 0, y = 1, IFMC-36-Tb; H3L is 4,4',4?-((2,2',2?-(nitrilotris(methylene))tris(1H-benzo[d]imidazole-2,1-diyl))tris(methylene))tribenzoic acid; IFMC = Institute of Functional Material Chemistry) have been successfully synthesized by taking advantage of different molar ratios of lanthanide(III) (Ln(III)) and metalloligands under solvothermal conditions. Further luminescent measurements indicate that IFMC-36-Eu(x)Tb(y) exhibits characteristic sharp emission bands of Eu(III) and Tb(III), and the intensities of red and green can be modulated correspondingly by tuning the ratios of Eu(III) and Tb(III). Particularly, the solvent-dependent luminescent behavior of IFMC-36-Eu shows a potential application in detection of small-molecule pollutant nitrobenzene by significant fluorescence quenching. Furthermore, IFMC-36-Eu displays preeminent anti-interference ability and could be used for sensing in the systems with complicated components. This is the first time that a d-f heterometallic-organic framework can be investigated as a chemical sensor for selective, sensitive, and recyclable detection of nitrobenzene.
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Bonding interactions between sulfur dioxide (SO?) and mono-ruthenium(II)-substituted Keggin-type polyoxometalates: electronic structures of ruthenium-SO? adducts.
Phys Chem Chem Phys
PUBLISHED: 07-23-2014
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Density functional theory (DFT) calculations and natural bond orbital (NBO) analysis were carried out to investigate the electronic structures and bonding features between the ruthenium(ii) atom and the SO2 molecule in two ruthenium-sulfur dioxide (SO2) adducts, trans-Ru(NH3)4(SO2)Cl(+) and [{SiW11O39}Ru(II)(SO2)](6-). In addition, the bonding interactions between SO2 and the metal-ruthenium fragment were determined by binding energy (?Eabs) calculation and electronic structures. The results indicate that the ?(1)-S-planar model in both trans-Ru(NH3)4(SO2)Cl(+) and [{SiW11O39}Ru(II)(SO2)](6-) are more favorable. NBO analysis of the bonding interaction between ruthenium and sulfur centers in the [{SiW11O39}Ru(II)(SO2)](6-) complex shows that it possesses a ? and a ? bond. It predicts that the polyoxometalate [SiW11O39Ru](6-) can serve as a potential adsorbent for the SO2 molecule because of the strong Ru-S bond relative to Ru(NH3)4Cl(+).
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Superatoms (Li3O and BeF3) induce phenalenyl radical ?-dimer: fascinating interlayer charge-transfer and large NLO responses.
Dalton Trans
PUBLISHED: 07-11-2014
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Recently, the well-known phenalenyl radical ?-dimer with its fascinating 2-electron/12-center (2e/12c) bond has attracted our attention. In this work, we designed two molecules, Li3OC13H9 () and BeF3C13H9 (). Interestingly, owing to the inductive effect of superatoms, an electron is transferred from Li3O to phenalenyl in , while an electron is transferred from phenalenyl to BeF3 in . Further, we employed and as building blocks to assemble two novel molecules with 2e/12c bonds: Li3O(C13H9)2BeF3 () and Li3O(C13H9)2BeF3 (). Remarkably, and with novel 2e/12c bonds exhibit a dramatic interlayer charge-transfer character, which results in a significant difference of dipole moments (??: 2.6804 for and 3.8019 Debye for ) between the ground state and the crucial excited state. As a result, the static first hyperpolarizabilities (?0: 5154 for and 12?500 au for ) are considerably larger than the values of 347 for and 328 au for . It is our expectation that the results of the present work might provide beneficial information for further theoretical and experimental studies on the fascinating properties of molecules with interlayer charge-transfer character.
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Shedding light on the photophysical properties of iridium(III) complexes with N-heterocyclic carbene ligands from a theoretical viewpoint.
J Phys Chem A
PUBLISHED: 06-27-2014
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The phosphorescent efficiencies of the Ir(III) carbene complexes 1-3 with wide-range color tuning were focused on in this work. A DFT/TDDFT (density functional theory/time-dependent density functional theory) investigation on the geometries in the ground and lowest triplet excited states, the frontier molecular orbitals, the absorption spectra, and d-orbital splittings of 1-3 were provided to get a better understanding of structure–property relationships. Importantly, to shed light on the difference in phosphorescent quantum yields for 1-3, radiative decay constants as well as zero-field-splitting parameters were calculated based on the estimation of spin–orbit coupling (SOC) matrix elements denoted as T(?1)|H(SOC)|S(n). The results show that, for any complex, the radiative decay rates in the three substates (namely, T(x), T(y), and T(z0) are not equal, and the largest radiative rates of 1-3 are all located in x substates with values of 1.0764 × 10(4), 0.8231 × 10(4), and 1.9596 × 10(4) s(–1), respectively. Moreover, for 3 with the highest quantum efficiency, we make efforts to modify it through varying substituents and substituent positions not only to achieve blue shift in the emission but also to obtain improved triplet energy.
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Self-assembly of an all-thiol-stabilized {Ag??S??} high-nuclearity luminescent nanocluster with a "crab-like" shape.
Dalton Trans
PUBLISHED: 06-13-2014
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We report a rare all-thiol-stabilized [Ag28(S(t)Bu)23](5+) ({Ag28S23} for short) nanocluster with a "crab-like" shape in compound [Ag28(S(t)Bu)23](CF3COO)5·8CH3OH (1), which has been synthesized by the self-assembly of AgS(t)Bu with CF3COOH, Et3N and KBr/KI in methanol. The diffuse reflection spectrum and luminescence spectra of 1 were investigated.
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The Effect of the different spin multiplicity on nonlinear optical properties of lithium decahydroborate dimers.
J Mol Model
PUBLISHED: 05-31-2014
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In 2009, an innovative type of lithium decahydroborate (Li@B(10)H(14)) complex with a basketlike complexant of decaborane (B(10)H(14)) was designed and studied. Theoretical investigation is very important for designing high-performance nonlinear optical (NLO) materials. In the present work, an unusual Li@B(10)H(14) dimer with different spin multiplicities was designed theoretically to explore the influence of the spin multiplicity on NLO properties: 1 (triplet), 2 (open-shell singlet) and 3 (singlet). Interestingly, the results show that the intersection angle (between cage A and cage A') follows the order of 1 (13.71°)?>?2 (1.65°)?>?3 (0°). As a result, the first hyperpolarizability (?(tot)) value follows the order of 1 (19,129 a.u.)?
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A novel organic-inorganic hybrid constructed from the Nyman-type dititanoniobate [Ti2Nb8O28](8-) and copper-organic cations.
Dalton Trans
PUBLISHED: 05-28-2014
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A new organic-inorganic hybrid titaniobate compound, [Cu(en)2][Cu(en)2(H2O)2]3[Ti2Nb8O28]·8H2O (1) (en = ethylenediamine), was successfully synthesized, characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA) and UV-Vis diffuse reflectance spectroscopy and its photoluminescence studied.
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[Analysis of HIV genotypic drug resistance among pediatric HIV/AIDS cases with virological failure after free antiretroviral therapy in Yunnan province].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 05-24-2014
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To assess the prevalence and the characteristics of HIV-1 drug-resistance in pediatric HIV/AIDS cases with virological failure after free antiretroviral therapy in Yunnan Province.
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A novel 3D inorganic heteropoly blue as visible light responsive photocatalyst.
Dalton Trans
PUBLISHED: 05-23-2014
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A new 3D extended heteropoly blue Ba4[SiW(V)4W(VI)8O40]·H2O (1) composed of twelve-coordinated ?-Keggin anions [SiW(V)4W(VI)8O40](8-) and eight-coordinated Ba sites {BaO8} has been hydrothermally synthesized and fully characterized by elemental analysis, IR spectroscopy, XPS, single crystal X-ray and X-ray powder (XRPD) diffraction. 1 represents the first inorganic 3D framework constructed from four-electron reduced ?-Keggin anions linked by alkaline earth metals. The photocatalytic activity of 1 has been evaluated for rhodamine B (RhB) degradation. 1 exhibits excellent catalytic activity for the degradation of RhB in the presence of H2O2and the involvement of visible light makes a more complete degradation. The results of the current study suggest that multi-electron reduced polyoxometalates can catalyze efficient degradation of an organic dye with H2O2.
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Direct common gram-negative bacterial identification from positive blood culture bottles by SELDI-TOF MS.
J. Microbiol. Methods
PUBLISHED: 05-22-2014
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A protein database was constructed and validated with identification rate over 90% for the 4 most common Gram-negative bacteria on agar plates. By protein masses comparison, 120 bacteria of the 4 species from blood culture bottles were identified. The concordance was high (Kappa=0.906) between our method and conventional approach.
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The V-shaped polar molecules encapsulated into Cs (10528)-C72: stability and nonlinear optical response.
Dalton Trans
PUBLISHED: 05-20-2014
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Recently, a new sulfide cluster fullerene, Sc2S@Cs (10528)-C72 containing two pairs of fused pentagons has been isolated and characterized (Chen et al., J. Am. Chem. Soc., 2012, 134, 7851). Inspired by this investigation, we propose a question: what properties will be influenced by the interaction between the encapsulated V-shaped polar molecule and C72? To answer this question, four encapsulated metallic fullerenes (EMFs) M2N@C72 (M = Sc or Y, N = S or O) along with pristine Cs-C72 (10528) were investigated by quantum chemistry methods. The results show that the Egap (3.01-3.14 eV) of M2N@C72 are significantly greater than that of pristine Cs-C72 (10528) (2.34 eV). This indicates that the stabilities of these EMFs increase by encapsulating the V-shaped polar molecule into the fullerene. Furthermore, the natural bond orbital (NBO) charge analysis indicates electron transfer from M2N to C72 cage, which plays a crucial role in enhancing first hyperpolarizability (?tot). The ?tot follows the order of 1174 au (Y2O@C72) ? 1179 au (Sc2O@C72) > 886 au (Y2S@C72) ? 864 au (Sc2S@C72) > 355 au (C72). This indicates that the ?tot of M2N@C72 is more remarkable than that of pristine Cs-C72 (10528) due to the induction effect of the encapsulated molecule. Compared with sulfide cluster fullerenes (Y2S@C72 and Sc2S@C72), oxide cluster fullerenes (Sc2O@C72 and Y2O@C72) show much larger ?tot due to the small ionic radius and the large electronegativity of oxygen. In contrast, the metal element (scandium and yttrium) has a slight influence on the ?tot. Thus, oxide cluster fullerenes are candidates to become promising nonlinear optical materials with higher performance.
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Infantile spasms in a boy with an abnormal karyotype (46, XY, der(9)t(7;9)(p15;p22)pat).
Neurol India
PUBLISHED: 05-15-2014
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Infantile spasm (IS) is an epilepsy syndrome affecting infants and young toddlers and many causes have been reported, including occasional chromosomal abnormalities. We describe a 6-month-oldboy who experienced his first seizure at 5 months of age. The seizures were characterized by brief head nods and forceful flexion of the trunk and limbs. The patient has been developmentally delayed since birth and had deteriorated remarkably in the last month. Interictal electroencephalography showed modified hypsarrhythmia. Magnetic resonance imaging showed delayed myelination and widened brain extracellular space. Chromosomal analysis revealed the karyotype 46, XY, der(9) t(7;9)(p15;p22) pat. His father has the asymptomatic reciprocal translocation t(7;9)(p15;p22). This chromosomal abnormality is probably the etiology for the ISs and severe developmental anomalies in this patient. Chromosomal analysis may be done in patients with IS with no obvious cause.
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A cationic iridium(III) complex with aggregation-induced emission (AIE) properties for highly selective detection of explosives.
Chem. Commun. (Camb.)
PUBLISHED: 04-28-2014
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A new cationic Ir(III) complex with AIE characteristics was designed and synthesized with the help of density functional theory calculations, which exhibits highly sensitive and selective detection of explosives (2,4,6-trinitrophenol, TNP).
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Polyoxometalate-based cobalt-phosphate molecular catalysts for visible light-driven water oxidation.
J. Am. Chem. Soc.
PUBLISHED: 03-31-2014
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A series of all-inorganic, abundant-metal-based, high-nuclearity cobalt-phosphate (Co-Pi) molecular catalysts [{Co4(OH)3(PO4)}4(SiW9O34)4](32-) (1), [{Co4(OH)3(PO4)}4(GeW9O34)4](32-) (2), [{Co4(OH)3(PO4)}4(PW9O34)4](28-) (3), and [{Co4(OH)3(PO4)}4(AsW9O34)4](28-) (4) were synthesized and shown to be highly effective at photocatalytic water oxidation. The {Co16(PO4)4} cluster contains a Co4O4 cubane which is structurally analogous to the [Mn3CaO4] core of the oxygen-evolving complex (OEC) in photosystem II (PSII). Compounds 1-4 were shown to be the first POM-based Co-Pi-cluster molecular catalysts for visible light-driven water oxidation, thus serving as a functional model of the OEC in PSII. The systematic synthesis of four isostructural analogues allowed for investigating the influence of different heteroatoms in the POM ligands on the photocatalytic activities of these Co-Pi cluster WOCs. Further, the POM-based photocatalysts readily recrystallized from the photocatalytic reaction systems with the polyoxoanion structures unchanged, which together with the laser flash photolysis, dynamic light-scattering, (31)P NMR, UV-vis absorption, POM extraction, and ICP-MS analysis results collectively confirmed that compounds 1-4 maintain their structural integrity under the photocatalytic conditions. This study provides not only a valuable molecular model of the "Co-Pi" catalysts with a well-defined structure but also an unprecedented opportunity to fine-tune high-nuclearity POM clusters for visible light-driven water splitting.
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A microporous anionic metal-organic framework for sensing luminescence of lanthanide(III) ions and selective absorption of dyes by ionic exchange.
Chemistry
PUBLISHED: 03-27-2014
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Herein, a novel anionic framework with primitive centered cubic (pcu) topology, [(CH3 )2 NH2 ]4 [(Zn4 dttz6 )Zn3 ]?15?DMF?4.5?H2 O, (IFMC-2; H3 dttz=4,5-di(1H-tetrazol-5-yl)-2H-1,2,3-triazole) was solvothermally isolated. A new example of a tetranuclear zinc cluster {Zn4 dttz6 } served as a secondary building unit in IFMC-2. Furthermore, the metal cluster was connected by Zn(II) ions to give rise to a 3D open microporous structure. The lanthanide(III)-loaded metal-organic framework (MOF) materials Ln(3+) @IFMC-2, were successfully prepared by using ion-exchange experiments owing to the anionic framework of IFMC-2. Moreover, the emission spectra of the as-prepared Ln(3+) @IFMC-2 were investigated, and the results suggested that IFMC-2 could be utilized as a potential luminescent probe toward different Ln(3+) ions. Additionally, the absorption ability of IFMC-2 toward ionic dyes was also performed. Cationic dyes can be absorbed, but not neutral and anionic dyes, thus indicating that IFMC-2 exhibits selective absorption toward cationic dyes. Furthermore, the cationic dyes can be gradually released in the presence of NaCl.
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Recent advances in porous polyoxometalate-based metal-organic framework materials.
Chem Soc Rev
PUBLISHED: 03-27-2014
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Polyoxometalate (POM)-based metal-organic framework (MOF) materials contain POM units and generally generate MOF materials with open networks. POM-based MOF materials, which utilize the advantages of both POMs and MOFs, have received increasing attention, and much effort has been devoted to their preparation and relevant applications over the past few decades. They have good prospects in catalysis owing to the electronic and physical properties of POMs that are tunable by varying constituent elements. In this review, we present recent developments in porous POM-based MOF materials, including their classification, synthesis strategies, and applications, especially in the field of catalysis.
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Effect of RFRP-3 on reproduction is sex- and developmental status-dependent in the striped hamster (Cricetulus barabensis).
Gene
PUBLISHED: 03-17-2014
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RFamide-related peptides (RFRPs) are orthologous to gonadotropin-inhibitory hormone (GnIH) inhibiting gonadotropin release. There are only two RFRP sequences (RFRP-1 and RFRP-3) encoded in rodents. RFRP-3, which was considered as a hypothetical inhibitor on GnRH, shows a stimulatory effect on the male Syrian and male Siberian hamster in short days. As a dominant rodent pest in northern China farmland, the striped hamster (Cricetulus barabensis) has higher reproductive activities and could act as a model to study the mechanism of reproduction. However, the effect of RFRP-3 on the reproductive activity for the striped hamster is less understood. In the study, we cloned 643 bp RFRP cDNA from the striped hamster hypothalamus, which contained an ORF of 570 bp encoding two RFamide-related peptide (RFRP) sequences: SPAPANKVPHSAANLPLRF-NH2 (C. barabensis RFRP-1) and TLSRVPSLPQRF-NH2 (C. barabensis RFRP-3). We also investigated the expression variation of RFRP mRNA and GnRH mRNA in the hypothalamus from hamsters with different developmental statuses (7-week-, 13-week- and 1.5-year-olds) using FQ-PCR, in which the 13-week-old female individuals were in estrous. The striped hamsters that are 7 weeks and 1.5 years old are non-breeding individuals, and those that are 13-week hamsters have breeding phenomena. The highest hypothalamus RFRP mRNA level was found in breeding males as compared to non-breeding males. Conversely, the lowest RFRP mRNA level in the hypothalamus was observed in breeding females, with no significant level when the breeding females were compared to the 7-week-old individuals. Additionally, the investigation of GnRH expression level showed a declining expression trend across the developmental stages (7-week-, 13-week- and 1.5-year-olds) in both sexes. Significant negative and positive relationships were detected in the 13-week estrous female (r=-0.997, P=0.035) and the 13-week male (r=0.998, P=0.029) striped hamsters respectively, which suggest that RFRP-3 has inhibitory and stimulatory effects on female and male adults respectively. Our results suggest that the effects of RFRP-3 on reproduction are sex- and developmental status-dependent in the striped hamster.
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MicroRNA-204, a direct negative regulator of ezrin gene expression, inhibits glioma cell migration and invasion.
Mol. Cell. Biochem.
PUBLISHED: 03-12-2014
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Ezrin is overexpressed in a variety of neoplastic cells and involved in the later stages of tumor progression and metastasis. Ezrin expression can be regulated at both the transcriptional and post-transcriptional levels. We used a combination of bioinformatics and experimental techniques to demonstrate that the miR-204 is a direct negative regulator of ezrin. Overexpression of miR-204 mimics decreased the activity of a luciferase reporter containing the ezrin 3' UTR and led to repression of ezrin protein. In contrast, ectopic expression of miR-204 inhibitor elevated ezrin expression. We also show that miR-204 is down-regulated in a panel of glioma tissues and in high invasive glioma cell lines we examined. Moreover, miR-204 mimics significantly reduced glioma cell migration and invasion, while miR-204 inhibitor generated the opposite results. Finally, overexpression of miR-204 and knockdown of ezrin reduced glioma cell invasion, and these effects could be rescued by re-expression of ezrin. These findings reveal that miR-204 could be partly due to its inhibitory effects on glioma cell migration and invasion through regulating ezrin expression.
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Theoretical studies on organic D-?-A sensitizers with planar triphenylamine donor and different ?-linkers for dyes-sensitized solar cells.
J Mol Model
PUBLISHED: 03-06-2014
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Systematic density functional theory (DFT) and time-dependent DFT calculations on the geometry, electronic structure, absorption, and nonlinear optical (NLO) properties of experimentally synthesized organic sensitizers LCn (n?=?1-3) used in dyes-sensitized solar cells (DSSCs) were performed to disclose the important influences of the planar triphenylamine donor and the extended ?-linker on the DSSCs performance. The interaction of dye with I2 and the conduction band shift were also investigated to rationalize the difference in open-circuit photovoltage (V oc). The results demonstrated that the planarization of TPA donor and the extended conjugation of ?-linker in sensitizers LC2 and LC3 could result in a red shift of absorption and a reduction in exciton binding energy, which is beneficial to enhance the matching degree of absorption of sensitizers with solar photon-flux spectrum and to improve the incident photon-to-current conversion efficiency, both contributing to the significant increase of photocurrent density as compared to reference dye LC1. It is also found that the calculated NLO properties correlated well with the photocurrent response of sensitizers, suggesting that NLO properties may be used as an effective tool for the fast screen and design of candidate sensitizers. As for candidate dyes Tn (n?=?1-4) with different dithiophene blocks as ?-linker, dye T1 with dithienosilole as ?-linker may serve as a promising alternative to high-performance dye LC3.
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Intervention effects of QRZSLXF, a Chinese medicinal herb recipe, on the DOR-?-arrestin1-Bcl2 signal transduction pathway in a rat model of ulcerative colitis.
J Ethnopharmacol
PUBLISHED: 03-06-2014
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Qingre Zaoshi Liangxue Fang (QRZSLXF) is a Chinese medicinal herb recipe that is commonly prescribed for the treatment of ulcerative colitis. It includes 5 quality assured herbs: Sophora flavescens Aiton., Baphicacanthus cusia (Nees) Bremek., Bletilla striata Rchb.f., Glycyrrhiza uralensis Fisch. and Coptis chinensis Franch. The main phytochemical ingredient of QRZSLXF includes ammothamnine, sophocarpidine, liquiritin, berberine and indirubin. QRZSLXF has been clinically proven for use in the treatment of ulcerative colitis for over twenty years. In the past ten years, research has confirmed the therapeutic effect of QRZSLXF in ulcerative colitis and partially revealed its mechanism of action. Here, we further reveal the therapeutic mechanism of QRZSLXF in ulcerative colitis. To investigate the role of the DOR-?-arrestin1-Bcl-2 signal transduction pathway in ulcerative colitis and to determine the effects of QRZSLXF on this signal transduction pathway.
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Structures and electro-optical properties of Möbius [n]Cyclacenes[13-18]: a theoretical study.
J Mol Model
PUBLISHED: 03-04-2014
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Due to the unusual properties of the Möbius cyclacenes (MC) such as ? electrons, MC has drawn the extensive attention of scientists. In the present work, six [n]MC (n? =?13-18, n is the number of benzenoid rings) were systematically investigated to explore the size-dependent effects on structures, electro-optical properties, and frontier molecule orbits (FMO). According to the dihedral angles (C-C-C-C), the un-twisted area and twisted area are defined, respectively. The twisted area mainly distributes on seven or eight benzenoid rings for [n]MC (n? =?13-18). Further, the polarizability (??) and first hyperpolarizability (??) of [n]MC (n? =?13-18) were calculated with three density functional methods (BHandHLYP, Cam-B3LYP, and M06-2X). Results show that the ?? values increase linearly with increasing the number (n) of benzenoid rings. Significantly, the ?? values are increased to zigzag with increasing the number (n) of benzenoid rings. Interestingly, when n is even (14, 16, and 18), the electron transfer is from the twisted area to the un-twisted area, but the electron transfer is from the un-twisted area to the twisted area when n is odd (13, 15, and 17).
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Diversity and antibacterial activities of culturable fungi associated with coral Porites pukoensis.
World J. Microbiol. Biotechnol.
PUBLISHED: 02-28-2014
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The diversity of coral associated fungi is not enough understood, especially for scleractinian corals. Members of Porites are common and dominant species of scleractinian corals. To date, the fungal communities associated with coral Porites pukoensis have been not reported. In this paper, the diversity and activity of coral associated fungi in P. pukoensis were explored, 23 fungal strains were isolated, belonging to 10 genera and Aspergillus sp. (30.4 %) was predominant fungal genera. The sequence of isolate C1-23 in GenBank was only 90 % similarity to the most closely related sequences. It is concluded that rich fungal symbionts are attached to P. pukoensis, the rate of isolates with antibacterial activity was up to 30 %, particularly some isolates showed stronger bioactivities to gram-negative bacteria. It is included that the diversity of coral associated fungi in P. pukoensis is abundant and its activity is obviously. So the activities of fungi in P. pukoensis were deserved for further study.
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A fluorescent sensor for highly selective detection of nitroaromatic explosives based on a 2D, extremely stable, metal-organic framework.
Chemistry
PUBLISHED: 02-27-2014
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A 2D, extremely stable, metal-organic framework (MOF), NENU-503, was successfully constructed. It displays highly selective and recyclable properties in detection of nitroaromatic explosives as a fluorescent sensor. This is the first MOF that can distinguish between nitroaromatic molecules with different numbers of ?NO2 groups.
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Theoretical characterization and design of highly efficient iridium (III) complexes bearing guanidinate ancillary ligand.
J. Mol. Graph. Model.
PUBLISHED: 02-25-2014
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A density functional theory/time-depended density functional theory was used to investigate the synthesized guanidinate-based iridium(III) complex [(ppy)2Ir{(N(i)Pr)2C(NPh2)}] (1) and two designed derivatives (2 and 3) to determine the influences of different cyclometalated ligands on photophysical properties. Except the conventional discussions on geometric relaxations, absorption and emission properties, many relevant parameters, including spin-orbital coupling (SOC) matrix elements, zero-field-splitting parameters, radiative rate constants (kr) and so on were quantitatively evaluated. The results reveal that the replacement of the pyridine ring in the 2-phenylpyridine ligand with different diazole rings cannot only enlarge the frontier molecular orbital energy gaps, resulting in a blue-shift of the absorption spectra for 2 and 3, but also enhance the absorption intensity of 3 in the lower-energy region. Furthermore, it is intriguing to note that the photoluminescence quantum efficiency (?PL) of 3 is significantly higher than that of 1. This can be explained by its large SOC value(n=3-4) and large transition electric dipole moment (?S3), which could significantly contribute to a larger kr. Besides, compared with 1, the higher emitting energy (ET1) and smaller (2) value for 3 may lead to a smaller non-radiative decay rate. Additionally, the detailed results also indicate that compared to 1 with pyridine ring, 3 with imidazole ring performs a better hole injection ability. Therefore, the designed complex 3 can be expected as a promising candidate for highly efficient guanidinate-based phosphorescence emitter for OLEDs applications.
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Redox-controlled ?-Dawson {Mn2(III)W17} polyoxometalate with photocatalytic H2 evolution activity.
Chem. Commun. (Camb.)
PUBLISHED: 02-15-2014
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A novel ?-Dawson [(WO5)3W14Mn2(III)O44Cl2](12-) compound induced by the Jahn-Teller distortion of Mn(III) has been synthesized through utilizing {Mn12} as a reactant, which exhibits photocatalytic H2 evolution activity. Its electrochemical behavior and magnetic properties were investigated.
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Influence of spiral framework on nonlinear optical materials.
Chemphyschem
PUBLISHED: 02-13-2014
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A series of spiral donor-?-acceptor frameworks (i.e. 2-2, 3-3, 4-4, and 5-5) based on 4-nitrophenyldiphenylamine with ?-conjugated linear acenes (naphthalenes, anthracenes, tetracenes, and pentacenes) serving as the electron donor and nitro (NO2 ) groups serving as the electron acceptor were designed to investigate the relationships between the nonlinear optical (NLO) responses and the spirality in the frameworks. A parameter denoted as D was defined to describe the extent of the spiral framework. The D value reached its maximum if the number of NO2 groups was equal to the number of fused benzene rings contained in the linear acene. A longer 4-nitrophenyldiphenylamine chain led to a larger D value and, further, to a larger first hyperpolarizability. Different from traditional NLO materials with charge transfer occurring in the one-dimensional direction, charge transfer in 2-2, 3-3, 4-4, and 5-5 occur in three-dimensional directions due to the attractive spiral frameworks, and this is of great importance in the design of NLO materials. The origin of such an enhancement in the NLO properties of these spiral frameworks was explained with the aid of molecular orbital analysis.
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Synthesis and anticonvulsant activity of ethyl 2,2-dimethyl-1-(2-substitutedhydrazinecarboxamido) cyclopropanecarboxylate derivatives.
Chem Biol Drug Des
PUBLISHED: 02-07-2014
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In this study on the development of new anticonvulsants, fourteen ethyl 2,2-dimethyl-1-(2-substitutedhydrazinecarboxamido) cyclopropanecarboxylate derivatives were synthesized and tested for anticonvulsant activity using the maximal electroshock, subcutaneous pentylenetetrazole screens, which are the most widely employed seizure models for early identification of candidate anticonvulsants. Their neurotoxicity was determined applying the rotorod test. Two compounds 6f and 6k showed promising anticonvulsant activities in both models employed for anticonvulsant evaluation. The most active compound 6k showed the maximal electroshock-induced seizures with ED50 value of 9.2 mg/kg and TD50 value of 387.5 mg/kg after intraperitoneally injection to mice, which provided compound 6k with a protective index (TD50/ED50 ) of 42.1 in the maximal electroshock test.
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Switchable NLO response induced by rotation of metallacarboranes [Ni(III/IV)(C2B9H11)2](-/0) and C-,B-functionalized derivatives.
Dalton Trans
PUBLISHED: 01-14-2014
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The rotary motion based on metallacarboranes around a molecular axis can be controlled by simple electron transfer processes, which provides a basis for the structure-property relationship for the nonlinear optical (NLO) switching. However, this phenomenon has not been previously reported in the development of NLO properties of metallacarboranes. In this work, the metallacarboranes [Ni(III/IV)(C2B9H11)2](-/0) and their C-,B-functionalized derivatives are studied by the density functional theory (DFT) method. By calculating relative energies, we obtained the stable states before and after rotation controlled by simple electron transfer. Then, the static and frequency-dependent second-order NLO properties were calculated by several DFT functionals. According to the TDDFT results, the large NLO responses of the studied compounds are mainly caused by substituent group-to-carborane cage charge transfer (L'LCT) and substituent group-to-metal charge transfer (L'MCT) processes. The order of first hyperpolarizabilities (? values) illustrates that the NLO response can be enhanced by introducing a strong electron-donating group. Significantly, the geometric interconversions resulting from the redox reaction of 1C/1T-6C/6T allow the NLO responses to be switched "ON" or "OFF". The B(9,9')-methoxyphenyl-functionalized derivative of nickelacarborane, having low energetic cost and large different NLO responses between two states (from 0 to 20?998 a.u.), can be an excellent switchable NLO material.
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A stable porous anionic metal-organic framework for luminescence sensing of ln(3+) ions and detection of nitrobenzene.
Chem Asian J
PUBLISHED: 01-08-2014
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A hexagonal channel-based porous anionic metal-organic framework was successfully constructed. IFMC-3 is stable in air and acidic/basic aqueous solutions at room temperature, and constitutes a selective luminescent sensing material for Ln(3+) ions and a recyclable probe for the sensitive detection of nitrobenzene.
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Suppressive effects of subchronic aluminum overload on the splenic immune function may be related to oxidative stress in mice.
Biol Trace Elem Res
PUBLISHED: 01-02-2014
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Aluminum (Al) is widely used in daily life and was recently recognized as a possible source of human intoxication because of its ability to accumulate in organs. The objective of the present study was to investigate the effects of subchronic Al overload on splenic immune function in mice. Furthermore, we have preliminarily explored its mechanism. The Al overload model was established via intragastric administration of Al once a day for 60 days. The body weight, spleen weight, and splenic coefficient were determined. The concentration of Al in the spleen was detected by inductively coupled plasma-mass spectrometry. The cytokine mRNA expression of spleen tissues was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Biochemical methods were used to detect superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) contents in spleen tissue. Body weight, spleen weight, and cytokine mRNA expression of spleen tissues were significantly reduced by Al overload. SOD and GSH-Px activities were also decreased, while the MDA content was increased in subchronic Al overload mice. The results indicate that subchronic exposure to aluminum trichloride (AlCl3) would result in Al accumulation, which suppressed spleen immune function through a mechanism related to oxidative stress.
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Geographic distance affects dispersal of the patchy distributed greater long-tailed hamster (Tscherskia triton).
PLoS ONE
PUBLISHED: 01-01-2014
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Dispersal is a fundamental process in ecology influencing the genetic structure and the viability of populations. Understanding how variable factors influence the dispersal of the population is becoming an important question in animal ecology. To date, geographic distance and geographic barriers are often considered as main factors impacting dispersal, but their effects are variable depending on different conditions. In general, geographic barriers affect more significantly than geographic distance on dispersal. In rapidly expanding populations, however, geographic barriers have less effect on dispersal than geographic distance. The effects of both geographic distance and geographic barriers in low-density populations with patchy distributions are poorly understood. By using a panel of 10 microsatellite loci we investigated the genetic structure of three patchy-distributed populations of the Greater long-tailed hamster (Tscherskia triton) from Raoyang, Guan and Shunyi counties of the North China Plain. The results showed that (i) high genetic diversity and differentiation exist in three geographic populations with patchy distributions; (ii) gene flow occurs among these three populations with physical barriers of Beijing city and Hutuo River, which potentially restricted the dispersal of the animal; (iii) the gene flow is negatively correlated with the geographic distance, while the genetic distance shows the positive correlation. Our results suggest that the effect of the physical barriers is conditional-dependent, including barrier capacity or individual potentially dispersal ability. Geographic distance also acts as an important factor affecting dispersal for the patchy distributed geographic populations. So, gene flow is effective, even at relatively long distances, in balancing the effect of geographic barrier in this study.
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Extremely low-frequency electromagnetic fields affect transcript levels of neuronal differentiation-related genes in embryonic neural stem cells.
PLoS ONE
PUBLISHED: 01-01-2014
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Previous studies have reported that extremely low-frequency electromagnetic fields (ELF-EMF) can affect the processes of brain development, but the underlying mechanism is largely unknown. The proliferation and differentiation of embryonic neural stem cells (eNSCs) is essential for brain development during the gestation period. To date, there is no report about the effects of ELF-EMF on eNSCs. In this paper, we studied the effects of ELF-EMF on the proliferation and differentiation of eNSCs. Primary cultured eNSCs were treated with 50 Hz ELF-EMF; various magnetic intensities and exposure times were applied. Our data showed that there was no significant change in cell proliferation, which was evaluated by cell viability (CCK-8 assay), DNA synthesis (Edu incorporation), average diameter of neurospheres, cell cycle distribution (flow cytometry) and transcript levels of cell cycle related genes (P53, P21 and GADD45 detected by real-time PCR). When eNSCs were induced to differentiation, real-time PCR results showed a down-regulation of Sox2 and up-regulation of Math1, Math3, Ngn1 and Tuj1 mRNA levels after 50 Hz ELF-EMF exposure (2 mT for 3 days), but the percentages of neurons (Tuj1 positive cells) and astrocytes (GFAP positive cells) were not altered when detected by immunofluorescence assay. Although cell proliferation and the percentages of neurons and astrocytes differentiated from eNSCs were not affected by 50 Hz ELF-EMF, the expression of genes regulating neuronal differentiation was altered. In conclusion, our results support that 50 Hz ELF-EMF induce molecular changes during eNSCs differentiation, which might be compensated by post-transcriptional mechanisms to support cellular homeostasis.
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Isomeric thiophene-fused benzocarborane molecules-different lithium doping effect on the nonlinear optical property.
Dalton Trans
PUBLISHED: 12-11-2013
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Recently, two isomeric thiophene-fused benzocarborane derivatives Tb1 and Tb2 with different locations of sulfur atoms, labeled as 1, 4 and 6, 9 of the thiophene were synthesized by Morisaki (Chem.-Eur. J., 2012, 18, 11251-11257) and Barrere (Macromolecules, 2009, 42, 2981-2987), respectively. In the present work, natural bond orbital (NBO) analysis shows that after doping one lithium atom into the isomeric structures Tb1 and Tb2, the electrons transfer to different regions in Tb1 and Tb2. For Tb1-Li, the transferred electrons mainly locate at S1, C2, C3, and S4, but for Tb2-Li, the transferred electrons mainly locate at C2, C3, C7, and C8. Significantly, the charge distribution is a crucial factor influencing the static first hyperpolarizabilities for Tb1-Li and Tb2-Li. Furthermore, the ?tot value of Tb1-Li is 6222 au, which is about 160 times larger than that of Tb1 (39 au). However, the ?tot value of Tb2-Li (498 au) is only about 5 times larger than that of the corresponding Tb2 (91 au). It is our expectation that this work could provide useful information for the development of nonlinear optical materials based on carboranes.
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[Autophagy expression and its significance in chondrocytes from a degenerate model of human cervical endplate].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 12-05-2013
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To explore the autophagy expression and examine its significance in chondrocytes in a degenerate model of human cervical vertebrae endplate.
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Optical trapping of red blood cells in living animals with a water immersion objective.
Opt Lett
PUBLISHED: 11-28-2013
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We demonstrate optical trapping of red blood cells (RBCs) in living animals by using a water immersion objective. First, the cells within biological tissue are mimicked by the particles immersed in aqueous solutions of glycerol. The optical forces depending on trapping depth are investigated when a parallel laser beam enters the water immersion objective. The results show that the optical forces vary with trapping depth, and the optimal trapping depth in aqueous solutions of glycerol (n=1.39) is 50 ?m. Second, the optimal trapping depth in aqueous solutions of glycerol can be changed by altering the actual tube length of the water immersion objective. Finally, we achieved optical trapping and manipulation of RBCs in living mice.
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Theoretical exploration of photoisomerization-switchable second-order nonlinear optical responses of two-dimendional ?- and w-shaped polyoxometalate derivatives of dithienylperfluorocyclopentene.
J Phys Chem A
PUBLISHED: 10-07-2013
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The switchable second-order nonlinear optical (NLO) properties on two-dimensional (2D) molecules based on Lindqvist-type [Mo6O19](2-) and dithienylperfluorocyclopentene (DTE) have been investigated at density functional theory (DFT) level. The CAM-B3LYP and M06-2X functionals were employed to study the switching behavior on NLO properties by photoisomerization reaction. The ?tot value of system 2c (closed-ring form) is 15920.5 au, which is 150.1 times larger than that of the corresponding open-ring form (system 2o). The time-dependent DFT calculations predict that the charge transfer from DTE to polyoxometalate, and DTE intramolecular charge transfer in closed-ring systems effectively improve the static first hyperpolarizability. Furthermore, the ?-shaped systems possess a larger u value than those of W-shaped systems owing to different orientation for substituent groups.
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Theoretical investigation on the 2e/12c bond and second hyperpolarizability of azaphenalenyl radical dimers: strength and effect of dimerization.
J Chem Phys
PUBLISHED: 10-05-2013
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An increasing number of chemists have focused on the investigations of two-electron/multicenter bond (2e/mc) that was first introduced to describe the structure of radical dimers. In this work, the dimerization of two isoelectronic radicals, triazaphenalenyl (TAP) and hexaazaphenalenyl (HAP) has been investigated in theory. Results show TAP2 is a stable dimer with stronger 2e/12c bond and larger interaction energy, while HAP2 is a less stable dimer with larger diradical character. Interestingly, the ultraviolet-visible absorption spectra suggest that the dimerization induces a longer wavelength absorption in visible area, which is dependent on the strength of dimerization. Significantly, the amplitude of second hyperpolarizability (?(yyyy)) of HAP2 is 1.36 × 10(6) a.u. that is larger than 7.79 × 10(4) a.u. of TAP2 because of the larger diradical character of HAP2. Therefore, the results indicate that the strength of radical dimerization can be effectively detected by comparing the magnitude of third order non-linear optical response, which is beneficial for further theoretical and experimental studies on the properties of complexes formed by radical dimerization.
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A novel treatment regimen for Duchenne muscular dystrophy.
Neuroreport
PUBLISHED: 09-19-2013
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Duchenne muscular dystrophy (DMD) is the most common, X-linked genetic, skeletal muscle disease, with various regimens of treatment. The objective of this study was to determine the safety and efficacy of a novel treatment regimen for this disease. Thirty boys with DMD were administered prednisone according to the following regimen: in the first year, 1.5 mg/kg/day for the first 3 months, 1.0 mg/kg/day for the next 3 months, 0.75 mg/kg/day for the next 3 months, and 0.5 mg/kg/day for the last 3 months. In the second year, prednisone was administered 0.5 mg/kg on the alternate day for 12 months. The muscle strength (Medical Research Council sum score and Gowers sign), serum enzymes (creatine kinase, creatine kinase isoenzyme-2, and lactate dehydrogenase), pulmonary function (forced vital capacity, maximum voluntary ventilation), body weight, height, and BMI were determined before treatment and 3, 6, 9, 12, and 24 months after treatment. The results showed that the patients mean Medical Research Council sum score increased from 46.1 at the baseline to 53.6 at 12 months and was maintained at 24 months. Gowers sign disappeared in 22 (73.3%) patients at 12 months and 21 (70.0%) at 24 months. The serum levels of creatine kinase, creatine kinase isoenzyme-2, and lactate dehydrogenase decreased and pulmonary function improved after 24 months of treatment. Significantly increased weight gain, osteoporosis, and cushingoid features were not observed. Our results suggested that this novel prednisone regimen for DMD has similar efficacy and safety as other regimens.
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Dynamin 1-like-dependent mitochondrial fission initiates overactive mitophagy in the hepatotoxicity of cadmium.
Autophagy
PUBLISHED: 09-04-2013
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How cadmium (Cd) induces mitochondrial loss in the context of its hepatotoxic effects remains enigmatic. The purpose of the study was to investigate whether mitophagy contributes to mitochondrial loss in cadmium-induced hepatotoxicity and to determine the potential mechanism. In normal human liver L02 cells, we observed that Cd treatment led to a significant increase in LC3-II formation, the number of GFP-LC3 puncta and lysosomal colocalization with mitochondria. These results were associated with mitochondrial loss and bioenergetic deficit. Additionally, the abrogation of excessive mitophagy by ATG5 siRNA treatment efficiently suppressed the mitochondrial loss and cytotoxicity of Cd. Before overactivating mitophagy, Cd induced excessive mitochondrial fragmentation as a result of increasing dynamin 1-like (DNM1L) expression and enhancing the DNM1L mitochondrial translocation. Moreover, reversing the excessive mitochondrial fragmentation via the administration of DNM1L siRNA significantly inhibited the observed overactivation of mitophagy in Cd-induced hepatotoxicity. Notably, the selective DNM1L inhibitor Mdivi-1 blocked abnormal mitophagy and subsequently ameliorated Cd-induced hepatotoxicity in vivo. Together, our data indicated that Cd induces mitochondrial loss via the overactivation of mitophagy following DNM1L-dependent mitochondrial fragmentation. The balanced activity of DNM1L and mitophagy signaling may be a potential therapeutic approach to treat Cd-induced hepatotoxicity.
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Metal ion directed metal-organic rotaxane frameworks with intrinsic features of self-penetration and interpenetration.
Chem. Commun. (Camb.)
PUBLISHED: 08-16-2013
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Three novel self-catenated 4-connected uninodal (6(5)·8)- metal-organic rotaxane frameworks (MORFs) containing cucurbit[6]uril were constructed from the in situ trans/cis-configuration (1 : 1) of rotaxanes by taking advantage of a d(10) metal ion directed synthesis. It was revealed that the effect of hydrogen bonds and ?-? stacking interactions play significant roles in the self-assembly process.
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Generation of nondiffracting Bessel beam using digital micromirror device.
Appl Opt
PUBLISHED: 07-12-2013
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We experimentally demonstrated Bessel-like beams utilizing digital micromirror device (DMD). DMD with images imitating the equivalent axicon can shape the collimated Gaussian beam into Bessel beam. We reconstructed the 3D spatial field of the generated beam through a stack of measured cross-sectional images. The output beams have the profile of Bessel function after intensity modulation, and the beams extend at least 50 mm while the lateral dimension of the spot remains nearly invariant. Furthermore, the self-healing property has also been investigated, and all the experimental results agree well with simulated results numerically calculated through beam propagation method. Our observations demonstrate that the DMD offers a simple and efficient method to generate Bessel beams with distinct nondiffracting and self-reconstruction behaviors. The generated Bessel beams will potentially expand the applications to the optical manipulation and high-resolution fluorescence imaging owing to the unique nondiffracting property.
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Three Cobalt(II)-Linked {P8 W48 } Network Assemblies: Syntheses, Structures, and Magnetic and Photocatalysis Properties.
Chem Asian J
PUBLISHED: 06-28-2013
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Three cobalt(II)-containing tungstophosphate compounds, Na8 Li8 Co5 [Co5.5 (H2 O)19 P8 W48.5 O184 ]?60?H2 O (1), K2 Na4 Li11 Co5 [Co7 (H2 O)28 P8 W48 O184 ]Cl? 59?H2 O (2), and K2 Na4 LiCo11 [Co8 (H2 O)32 P8 W48 O184 ](CH3 COO)4 Cl?47?H2 O (3), have been synthesized and characterized by IR spectroscopy, thermogravimetric analysis, elemental analyses, and magnetic measurements. The pH value impacts the formation of distinct cobalt-linked frameworks. The cyclic cavity of the polyanion accommodates 5.5, 7, and 8 cobalt ions in 1, 2, and 3, respectively. In compounds 1 and 2, each {Co5.5 P8 W48 } and {Co7 P8 W48 } fragment links to four others through multiple {Co-O-W} coordination bonds to generate a two-dimensional network. Compound 3 can be considered as a 3D network based on the {Co-O-W} coordination bonds and the {Co3 (CH3 COO)2 (H2 O)10 } linkers between the {P8 W48 } fragments. Interestingly, acetate ligands have been employed to form the {Co3 (CH3 COO)2 (H2 O)10 } unit, thereby inducing the construction of a 12-connected framework. To the best of our knowledge, compound 3 contains the largest-ever number of cobalt ions in a {P8 W48 }-based polyoxometalate when counterions are taken into account and the {P8 W48 } unit shows the highest number of connections thanks to the carboxyl bridges. The UV/Vis diffuse reflectance spectra of these powder samples indicate that the corresponding well-defined optical absorption associated with Eg can be assessed at 2.58, 2.48, and 2.73?eV and reveal the presence of an optical band gap. The photocatalytic H2 evolution activities of these {P8 W48 }-based compounds are evaluated.
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JNK phosphorylation promotes degeneration of cervical endplate chondrocytes through down-regulation of the expression of ANK in humans.
Chin. Med. J.
PUBLISHED: 06-18-2013
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C-Jun N-terminal kinase (JNK) signaling pathway and ankylosis gene (ANK) play a critical role in endplate chondrocytes degeneration. The purpose of this study was to investigate whether the expression levels of ANK was associated with the activation of JNK.
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DFT characterization on the mechanism of water splitting catalyzed by single-Ru-substituted polyoxometalates.
Dalton Trans
PUBLISHED: 06-13-2013
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Water oxidation is a key half reaction in the energy conversion scheme. The reaction mechanism for the oxidation of H2O to O2 catalyzed by single-Ru-substituted polyoxometalates, [Ru(III)(H2O)XW11O39](n-) (X = Si(IV), Ge(IV)), was investigated by means of density functional calculations. The electronic structure of the pre-activation intermediates indicates that the aqua ligand is prone to accommodate the proton coupled electron transfer (PCET) process to achieve the active group [Ru(V)=Oa], and the high valent oxo-ruthenium(V) species are responsible for the O-O forming event. Three possible proton acceptors were designed for the rate-determining step (Ob, Oa, and H2O), the calculated results support that the bridge Ob atom of the polytungstate ligand will act as the most favorable proton acceptor in the O-O bond formation, with an energy barrier of 28.43 kcal mol(-1). A detailed information of the peroxidic intermediates in the oxidation process was also characterized, both the peroxo-species [Ru(IV)(OO)SiW11O39](6-) and [Ru(V)(OO)SiW11O39](5-) show the six-coordinate isomer with an open terminal geometry is more favorable than the close seven-coordinate ones. In addition, the replacement of the heteroatom in XO4(n-) can effectively tune the catalytic activity of polyoxometalates, in the order of Ge(IV) > Si(IV).
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An unprecedented (3,4,24)-connected heteropolyoxozincate organic framework as heterogeneous crystalline Lewis acid catalyst for biodiesel production.
Sci Rep
PUBLISHED: 06-07-2013
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A novel 3D hexadecanuclear heteropolyoxozincate organic framework, IFMC-200, has been successfully synthesized based on a late transition metal-oxygen cluster. IFMC-200 not only represents the first example of (3,4,24)-connected framework but also contains the first 24-connected single metal cluster in a crystal structure. It exhibits superior thermal stability, good water-stability, and even insensitivity to the existence of acid and base within a certain range of pH values. Furthermore, it performs as a heterogeneous crystalline Lewis acid catalyst with good activity for the conversion of long-chain fatty acids rather than short-chain ones, and high recycling efficiency for esterification reaction of fatty acids with alcohols to produce biodiesel.
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Prediction of sweetness by multilinear regression analysis and support vector machine.
J. Food Sci.
PUBLISHED: 05-29-2013
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The sweetness of a compound is of large interest for the food additive industry. In this work, 2 quantitative models were built to predict the logSw (the logarithm of sweetness) of 320 unique compounds with a molecular weight from 132 to 1287 and a sweetness from 22 to 22500000. The whole dataset was randomly split into a training set including 214 compounds and a test set including 106 compounds, represented by 12 selected molecular descriptors. Then, logSw was predicted using a multilinear regression (MLR) analysis and a support vector machine (SVM). For the test set, the correlation coefficients of 0.87 and 0.88 were obtained by MLR and SVM, respectively. The descriptors found in our quantitative structure-activity relationship models are prone to a structural interpretation and support the AH/B System model proposed by Shallenberger and Acree.
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Efficient and tunable white-light emission of metal-organic frameworks by iridium-complex encapsulation.
Nat Commun
PUBLISHED: 04-25-2013
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Metal-organic frameworks (MOFs) are well known for their tunable structure and porosity. Many studies have shown they are promising for various important applications, for which their performance can be further enhanced by encapsulating functional species, such as luminescent guest molecules, within the frameworks. Although numerous MOFs are luminescent, very few emit white light and their quantum yield is usually low. Here we report a strategy to achieve efficient white-light emission by encapsulating an iridium complex in the MOF cavity. A mesoporous blue-emitting MOF is prepared as host to encapsulate a yellow-emitting iridium complex, [Ir(ppy)2(bpy)](+). The resultant composites emit bright white light with good colour quality (for example, Commission International de IEclairage coordinates, colour-rendering index and correlated colour temperature of (0.31, 0.33), 84.5 and 5409?K, respectively), and high quantum yield up to 115?°C. This strategy may open new perspectives for developing high-performance energy-saving solid-state lighting materials.
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Self-assembly versus stepwise synthesis: heterometal-organic frameworks based on metalloligands with tunable luminescence properties.
Chemistry
PUBLISHED: 04-22-2013
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A new family of heterometal-organic frameworks has been prepared by two synthesis strategies, in which IFMC-26 and IFMC-27 are constructed by self-assembly and IFMC-28 is obtained by stepwise synthesis based on the metalloligand (IFMC=Institute of Functional Material Chemistry). IFMC-26 is a (3,6)-connected net and IFMC-27 is a (4,8)-connected 3D framework. The metalloligands {Ni(H4 L)}(NO3 )2 are connected by binuclear lanthanide clusters giving rise to a 2D sheet structure in IFMC-28. Notably, IFMC-26-Eux Tby and IFMC-28-Eux Tby have been obtained by changing the molar ratios of raw materials. Owing to the porosity of IFMC-26, Tb(3+) @IFMC-26-Eu and Eu(3+) @IFMC-26-Tb are obtained by postencapsulating Tb(III) and Eu(III) ions into the pores, respectively. Tunable luminescence in metal-organic frameworks is achieved by the two kinds of doping methods. In particular, the quantum yields of heterometal-organic frameworks are apparently enhanced by postencapsulation of Ln(III) ions.
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Enhancing the luminescence properties and stability of cationic iridium(III) complexes based on phenylbenzoimidazole ligand: a combined experimental and theoretical study.
Dalton Trans
PUBLISHED: 04-20-2013
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Herein we designed and synthesized a series of cationic iridium(III) complexes with a phenylbenzoimidazole-based cyclometalated ligand, containing different numbers of carbazole moieties from zero to three (complexes 1-4). The photophysical and electrochemical properties of this series have been systematically investigated. The complexes exhibit strong luminescence in both solution and in neat films, as well as excellent redox reversibility. Introducing carbazole groups into the complexes is found to lead to substantially enhanced photoluminescence quantum efficiency in the neat film, but has little effect on the emitting color and excited-state characteristics as supported by density functional theory (DFT) results. DFT calculations also suggest that functionalized complexes 2-4 reveal better hole-transporting properties than 1. More importantly, all complexes effectively reduce the degradation reaction to some extent in metal-centered (³MC) excited-states, demonstrating their stability. Further studies indicate that restriction of opening of the structures in the ³MC state is caused by the unique molecular conformation of the phenylbenzoimidazole ligand, which is first demonstrated here in cationic iridium(III) complexes without intramolecular ?-? stacking. These results presented here would provide valuable information for designing and synthesizing highly efficient and stable cationic iridium(III) complexes suitable for the optical devices.
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Carcinogenicity prediction of noncongeneric chemicals by a support vector machine.
Chem. Res. Toxicol.
PUBLISHED: 04-11-2013
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The ability to identify carcinogenic compounds is of fundamental importance to the safe application of chemicals. In this study, we generated an array of in silico models allowing the classification of compounds into carcinogenic and noncarcinogenic agents based on a data set of 852 noncongeneric chemicals collected from the Carcinogenic Potency Database (CPDBAS). Twenty-four molecular descriptors were selected by Pearson correlation, F-score, and stepwise regression analysis. These descriptors cover a range of physicochemical properties, including electrophilicity, geometry, molecular weight, size, and solubility. The descriptor mutagenic showed the highest correlation coefficient with carcinogenicity. On the basis of these descriptors, a support vector machine-based (SVM) classification model was developed and fine-tuned by a 10-fold cross-validation approach. Both the SVM model (Model A1) and the best model from the 10-fold cross-validation (Model B3) runs gave good results on the test set with prediction accuracy over 80%, sensitivity over 76%, and specificity over 82%. In addition, extended connectivity fingerprints (ECFPs) and the Toxtree software were used to analyze the functional groups and substructures linked to carcinogenicity. It was found that the results of both methods are in good agreement.
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Iodine-templated assembly of unprecedented 3d-4f metal-organic frameworks as photocatalysts for hydrogen generation.
Chem. Commun. (Camb.)
PUBLISHED: 03-26-2013
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Unprecedented 3d-4f MOFs encapsulating infinite linear polyiodide chains were firstly reported using iodine molecules as a versatile precursor template. They possess high framework stability in acid/base aqueous solutions. The kinetics of iodine molecule release/recovery and UV-light photocatalytic H(2) evolution activities were investigated.
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pH-induced different crystalline behaviors in extended metal-organic frameworks based on the same reactants.
Dalton Trans
PUBLISHED: 03-26-2013
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pH-induced different crystalline behaviors based on the same reactants and reaction conditions are illustrated by our present study. Compound has been used for the adsorption and delivery of 5-FU.
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Population genetic data of a model symbiotic cnidarian system reveal remarkable symbiotic specificity and vectored introductions across ocean basins.
Mol. Ecol.
PUBLISHED: 03-24-2013
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The Aiptasia-Symbiodinium symbiosis is a promising model for experimental studies of cnidarian-dinoflagellate associations, yet relatively little is known regarding the genetic diversity of either symbiotic partner. To address this, we collected Aiptasia from 16 localities throughout the world and examined the genetic diversity of both anemones and their endosymbionts. Based on newly developed SCAR markers, Aiptasia consisted of two genetically distinct populations: one Aiptasia lineage from Florida and a second network of Aiptasia genotypes found at other localities. These populations did not conform to the distributions of described Aiptasia species, suggesting that taxonomic re-evaluation is needed in the light of molecular genetics. Associations with Symbiodinium further demonstrated the distinctions among Aiptasia populations. According to 18S RFLP, ITS2-DGGE and microsatellite flanker region sequencing, Florida anemones engaged in diverse symbioses predominantly with members of Symbiodinium Clades A and B, but also C, whereas anemones from elsewhere harboured only S. minutum within Clade B. Symbiodinium minutum apparently does not form a stable symbiosis with other hosts, which implies a highly specific symbiosis. Fine-scale differences among S. minutum populations were quantified using six microsatellite loci. Populations of S. minutum had low genotypic diversity and high clonality (R = 0.14). Furthermore, minimal population structure was observed among regions and ocean basins, due to allele and genotype sharing. The lack of genetic structure and low genotypic diversity suggest recent vectoring of Aiptasia and S. minutum across localities. This first ever molecular-genetic study of a globally distributed cnidarian and its Symbiodinium assemblages reveals host-symbiont specificity and widely distributed populations in an important model system.
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The symmetric and asymmetric thiophene-fused benzocarborane: structures and first hyperpolarizabilities.
J Mol Model
PUBLISHED: 03-23-2013
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The unusual properties of thiophene-fused benzocarborane have attracted a lot of interest in recent years due to their wide applications in photonics and optoelectronics. In the present work, nine molecules [M, N] (M, N are labeled as the number of thiophene rings on the left and right part, respectively) on the basis of thiophene-fused benzocarborane were considered. The first hyperpolarizability (? tot) values of three synthesized symmetric molecules [1, 1], [2, 2], [3, 3] (M=N, Chem. Eur. J 2012. 18, 11251-11257) and six asymmetric molecules [1, 2], [1, 3], [1, 4], [1, 5], [2, 3], [2, 4] (M?N) were investigated, ? tot values of symmetric molecules show the order: 39 of [1, 1]< 800 of [2, 2]< 903 au of [3, 3], which indicate that ? tot value increases with increasing the number of thiophene ring for symmetric molecules. The other order of ? tot values can be observed: 39 of [1, 1]< 800 of [1, 2]< 3553 of [1, 3]< 7998 of [1, 4]< 13049 au of [1, 5] and 66 of [2, 2]< 3240 of [2, 3]< 8029 au of [2, 4]. Interestingly, when sum of M and N is constant, larger difference between M and N is, larger ? tot value is: 800 au of [2, 2]< 3553 au of [1, 3]; 3240 au of [2, 3] < 7998 au of [1, 4]; 903 au of [3, 3]< 8029 au of [2, 4]< 13049 au of [1, 5]. Significantly, [1, 5] with six thiophene rings has the largest ? tot value (13049 au) which is greatly larger than 903 au of [3, 3] with six thiophene rings. Furthermore, the natural bond orbital (NBO) charge populations, the nucleus-independent chemical shift (NICS), the bond length alternation (BLA) of the nine molecules and crucial transition were studied in our work. We hope that the present work will be beneficial for future theoretical and experimental studies on the electro-optical properties of thiophene-fused benzocarborane molecules.
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Trapping red blood cells in living animals using optical tweezers.
Nat Commun
PUBLISHED: 03-22-2013
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The recent development of non-invasive imaging techniques has enabled the visualization of molecular events underlying cellular processes in live cells. Although microscopic objects can be readily manipulated at the cellular level, additional physiological insight is likely to be gained by manipulation of cells in vivo, which has not been achieved so far. Here we use infrared optical tweezers to trap and manipulate red blood cells within subdermal capillaries in living mice. We realize a non-contact micro-operation that results in the clearing of a blocked microvessel. Furthermore, we estimate the optical trap stiffness in the capillary. Our work expands the application of optical tweezers to the study of live cell dynamics in animals.
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All-solid-state hybrid solar cells based on a new organometal halide perovskite sensitizer and one-dimensional TiO2 nanowire arrays.
Nanoscale
PUBLISHED: 03-19-2013
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A novel organometal halide perovskite (CH3NH3PbI2Br) is synthesized and used as a visible light absorber to sensitize one-dimensional (1D) TiO2 nanowire arrays (NWAs) for all-solid-state hybrid solar cells. It achieved a power conversion efficiency (PCE) of 4.87% and an open circuit voltage (Voc) of 0.82 V, both higher than those of its analogue CH3NH3PbI3.
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