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Aiming at the problem of precision driving and vibration suppression for sensitive payloads on-orbit, this paper proposes a new compliant platform based on an embedded superstructure and a smart material actuator. Firstly, the main structure of the platform is designed and optimized to achieve the expected indicators via the response surface method. Then, the vibration reduction mechanism of the platform with the embedded superstructure is studied by establishing an equivalent model. Following that, a four-phase superstructure is matched and designed with a compact space, and the results are verified by finite element modal analysis. Finally, both the tensioning performance and vibration reduction performance under fixed frequency harmonic disturbance are studied via transient dynamic simulation. Based on the obtained results, directions for future improvements are proposed. The relevant conclusions can provide a reference for function integration of precision tensioning and vibration suppression. [ABSTRACT FROM AUTHOR]

Hypochlorous acid (HOCl) is widely used in daily production and life because of its green and strongly oxidizing properties. Additionally, as a vital reactive oxygen species (ROS), it is an innate immune system weapon and performs a critical function in many pathophysiology processes. In this paper, a novel water-soluble fluorescent probe, BMH, with excellent performance is designed and synthesized by simple condensation of benzocoumarin and 2-mercaptoethanol. BMH has specific selectivity, excellent sensitivity, ultra-fast response (<3 s), and a wide pH detection range. The fluorescence intensity of BMH has an excellent linear correlation with the concentration of HOCl in the scope of 0–10 μM, and the calculated detection limit (DL) is 2.45 nM. The intramolecular charge transfer (ICT) sensing mechanism of BL has been verified by fluorescence, UV, and MS studies as well as density functional theory (DFT) calculations. Furthermore, BMH can be incorporated into a solid-state visual sensor to detect HOCl conveniently. BMH was applied to detect HOCl-spiked actual water samples and achieved satisfying recovery rates. Also, the low-toxicity BMH can be successfully used to track changes in endogenous/exogenous HOCl in living cells. In short, BL provides a robust and reliable monitoring tool to reveal the biological functions of HOCl and ensure its safe use. [ABSTRACT FROM AUTHOR]

The three-dimensional porous Fe3O4@Cu2−xS–MoS2 framework is reported for the first time. The as-prepared 3D framework exhibits good structural stability, high surface area, enhanced adsorption capacity to substrates, and strong absorption in the NIR range. As a result, such hybrid frameworks exhibit excellent NIR-light photocatalytic activity and stable cycling for the direct arylation of heteroaromatics at room temperature. [ABSTRACT FROM AUTHOR]

The application of nanohybrids in water treatment by the catalytic degradation of various pollutants has attracted much attention from researchers. Here, the Pd/Fe3O4-PEI-RGO nanohybrids (1d) with high shape selectivity and high specific surface area have been synthesized by the dispersion of Pd NPs and Fe3O4 NPs on PEI modified graphene oxide sheets. These nanohybrids show superior catalytic activity toward methylene blue with a high degradation efficiency above 99% in the presence of NaBH4 in aqueous solution, which is attributed to the effects of the Pd NPs supported on reduced graphene oxide nanosheets. Meanwhile, the 1d catalyst can be easily separated from the reaction mixture by applying an external magnetic field. The catalyst was recycled nine times without showing any significant loss in its activity. Such features enable this catalyst for promising application in catalysis, environment, and new energy fields. [ABSTRACT FROM AUTHOR]

Low cost, high activity and selectivity, convenient separation, and increased reusability are the main requirements for noble-metal-nanocatalyst-catalyzed reactions. Despite tremendous efforts, developing noble-metal nanocatalysts to meet the above requirements remains a significant challenge. Here we present a general strategy for the preparation of strongly coupled Fe3O4 and palladium nanoparticles (PdNPs) to graphene sheets by employing polyethyleneimine as the coupling linker. Transmission electron microscopic images show that Pd and Fe3O4 nanoparticles are highly dispersed on the graphene surface, and the mean particle size of Pd is around 3 nm. This nanocatalyst exhibits synergistic catalysis by Pd nanoparticles supported on reduced graphene oxide (rGO) and a tertiary amine of polyethyleneimine (Pd/Fe3O4/PEI/rGO) for the Tsuji-Trost reaction in water and air. For example, the reaction of ethyl acetoacetate with allyl ethyl carbonate afforded the allylated product in more than 99 % isolated yield, and the turnover frequency reached 2200 h−1. The yield of allylated products was 66 % for Pd/rGO without polyethyleneimine. The catalyst could be readily recycled by a magnet and reused more than 30 times without appreciable loss of activity. In addition, only about 7.5 % of Pd species leached off after 20 cycles, thus rendering this catalyst safer for the environment. [ABSTRACT FROM AUTHOR]

A new fluorescent derivative (1) containing coumarin exhibits Fe(III)-selective strong yellow-green fluorescence in ethanol. This compound could be used as an “off-on” chemosensor and allow the detection of Fe3+by monitoring changes in absorption and fluorescence spectra. Upon addition of Fe3+, an overall emission change of 125-fold was observed. High selectivity and sensitivity were observed over other metal ions, mainly due to the spirolactam ring-opening power of Fe3+. The detection limit was as low as 5.6?ppb. Photo-induced electron transfer, coupled with intramolecular charge transfer are proposed to account for the observed spectral response. [ABSTRACT FROM PUBLISHER]

8-hydroxyquinoline-5-carbaldehyde-(benzotriazol-1′-acetyl)hydrazone1was synthesized and found to show sensitivity and selectivity to Mg2+. Compared to other metal ions, the fluorescence intensity of1increased 65-fold upon addition of Mg2+with a low detection limit of 2.4 ppb in acetonitrile. [ABSTRACT FROM AUTHOR]

A Schiff-base fluorescent sensor, 7-methoxychromone-3-carbaldehyde-(3′,4′-dimethyl)pyrrole hydrazone (MCPH), was synthesized. The new sensor showed high selectivity for Al3+ over other metal ions examined in acetonitrile. Upon binding Al3+, a significant fluorescence enhancement with a turn-on ratio over 101-fold was triggered. The detection limit of MCPH for Al3+ was 2.5 × 10−7 mol L−1. [ABSTRACT FROM AUTHOR]

A Schiff-base ligand derived from 1-phenyl-3-methyl-4-formyl-2-pyrazolin-5-one (PMFP) and isoniazid was prepared and its La(III) complex was characterized by X-ray single crystal diffraction. The La(III) is nine-coordinate in a space group P21/n. DNA-binding was investigated by UV-Vis, fluorescence titration, ethidium bromide displacement experiments, and viscosity measurements, which indicated that the ligand and La(III) complex strongly binds to calf thymus DNA presumably via groove binding and intercalation. The intrinsic binding constants of the ligand and La(III) complex were 0.86 × 105 and 2.46 × 105 mol L−1, respectively. Antioxidant data from hydroxyl radical scavenging experiments in vitro suggest that the La(III) complex possesses higher scavenging ratio than the free ligand, metallic salt, and some standard antioxidants like mannitol. [ABSTRACT FROM AUTHOR]

Structural analyses indicate that the ligand and lanthanide ions form mononuclear 10-coordinate ([Ln L2 · (NO3)2] · NO3 [Ln(III) = La, Sm, Nd, and Yb; L is chromone-3-carbaldehyde-(isonicotinoyl) hydrazone) complexes with 1 : 2 metal-to-ligand stoichiometry. DNA-binding studies show that the ligand and its lanthanide complexes can bind to calf thymus DNA via an intercalation mode with binding constants of 105 (mol L-1)-1, and the lanthanide complexes bind stronger than the free ligand alone. Antioxidant activities of the ligand and lanthanide complexes were determined by superoxide and hydroxyl radical scavenging methods in vitro. The ligand and complexes possess strong scavenging effects, and the lanthanide complexes show stronger antioxidant activities than the ligand and some standard antioxidants, such as vitamin C. [ABSTRACT FROM AUTHOR]

In this paper, two novel porphyrinogen-like macrocycle ligands were synthesized and characterized with elemental analyses, 1H NMR, FAB-Ms, and IR methods. [ABSTRACT FROM AUTHOR]

A multifunctional nanoprobe, which can be used for dual modal imaging and the detection of cancer cells, has been reported. [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel water-soluble fluorescent chemosensor based on naphthalene derivate was designed. [•] The fluorescent chemosensor for Al3+ could be synthesized simply. [•] The fluorescent sensor exhibited high selectivity for Al3+ in absolute water media (pH=7.0). [ABSTRACT FROM AUTHOR]

Abstract: Series LiFePO4/C materials have been prepared by a so-called reformative solid-coordination method, which uses citric acid as the coordination agent and carbon source. A monodenate coordination band of –COO-M was proved to form gradually and that would help to disperse Li+ or Fe2+ among the homogeneous gel during the grinding process. Impure phase Fe2P was detected out among the LiFePO4/C composites with increasing annealed temperature. The remnant coating carbon was considered to be the reductive under the pure nitrogen gas. The amounts of carbon, particle size and morphology were investigated in detail and all the results showed to be related to the formation of Fe2P. The electro-conductive Fe2P phase among LiFePO4/C composites acts as important role in increasing electronic conductivity and evidently improves the electrochemical performance of LiFePO4/C including the less polarization phenomenon, comparatively high reversible capability, stable cycling performance and slight trend of less loss of rate capability. [Copyright &y& Elsevier]

It is well-known that ClO- and SCN- can cause adverse effects on the environment and organisms; therefore, development of new strategies for detecting ClO- and SCN-, especially in water, are highly desirable. Here, we present luminous Eu(iii) complex-functionalized Fe3O4 nanoparticles encapsulated into zeolitic imidazolate framework materials (nano-ZIF-8) and successfully employ this nano-MOF as a fluorescence probe for selective and sensitive detection of ClO- and SCN-. The introduction of ClO- into nano-ZIF-8 solution induced a significant decrease in the characteristic fluorescence emission of Eu3+ at 613 nm. However, strong fluorescence emission was again observed when SCN- was successively injected into the prepared nano-ZIF-8-ClO-. Thus, a novel fluorescence system for simultaneous detection of free ClO- and SCN- was established. On the basis of the superior adsorption performance of nano-MOF materials, free residual ClO- and SCN- in water was rapidly, sensitively and selectively detected with a detection limit of 0.133 nM and 0.204 nM, respectively. Moreover, nano-ZIF-8 was successfully used for monitoring the concentration levels of ClO- and SCN- in specimens of tap water and Yellow River water. Furthermore, the reversibility and regeneration of nano-ZIF-8 in sensing ClO- and SCN- is advantageous for applications of nano-ZIF-8 in solid-state sensing and anti-counterfeiting. As far as we know, this is the first time that nano-MOFs have been used as a selective fluorescence probe for ClO-/SCN- detection and anti-counterfeiting.

The three-dimensional porous Fe3O4@Cu2-xS-MoS2 framework is reported for the first time. The as-prepared 3D framework exhibits good structural stability, high surface area, enhanced adsorption capacity to substrates, and strong absorption in the NIR range. As a result, such hybrid frameworks exhibit excellent NIR-light photocatalytic activity and stable cycling for the direct arylation of heteroaromatics at room temperature.

The combination of different fluorescent species into one nanostructure to develop fluorescent nanoparticles with multiple emission signatures by a single wavelength excitation has become a very popular research area in the field of multiplex bioanalysis, diagnostics, and multicolor imaging. However, these novel hybrids must be elaborately designed to ensure that the unique properties of each component are conveyed, i.e., fluorescent species and nanoparticles, and are maximized without serious interactions with each other. Herein, a first triple-fluorescence dumbbell nanoprobe with large Stokes shift based on incorporating fluorescein isothiocyanate (FITC) and lanthanide complexes onto Au-Fe3O4 NPs was synthesized. This hybrid displays well-resolved triple fluorescence emission, with FITC at 515 nm, Tb(III) complex at 545 nm, and Eu(III) complex at 616 nm under a single-excitation wavelength and is used for highly selective and sensitive colorimetric detection of Cu(2+) with a detection limit of 30 nM. Under different Cu(2+) concentrations, this hybrid exhibited distinguishable multiple colors under UV light, and the color could change in the presence of different concentrations of Cu(2+). This sensor for ratio/multianalyte microscopic imaging of Cu(2+) in HeLa cells and BHK cells was also demonstrated. Target molecules, such as folic acid, can be covalently attached to the fluorescent nanoparticle surface to serve as an effective probe for simultaneous multicolor imaging folate receptor-overexpressing HeLa cell lines in vitro.

The application of nanohybrids in water treatment by the catalytic degradation of various pollutants has attracted much attention from researchers. Here, the Pd/Fe3O4-PEI-RGO nanohybrids (1d) with high shape selectivity and high specific surface area have been synthesized by the dispersion of Pd NPs and Fe3O4 NPs on PEI modified graphene oxide sheets. These nanohybrids show superior catalytic activity toward methylene blue with a high degradation efficiency above 99% in the presence of NaBH4 in aqueous solution, which is attributed to the effects of the Pd NPs supported on reduced graphene oxide nanosheets. Meanwhile, the 1d catalyst can be easily separated from the reaction mixture by applying an external magnetic field. The catalyst was recycled nine times without showing any significant loss in its activity. Such features enable this catalyst for promising application in catalysis, environment, and new energy fields.

We have developed an efficient strategy for synthesizing a strongly coupled Au/Fe3O4/GO hybrid material to improve the catalytic activity, stability, and separation capability of Au nanoparticles (NPs) and Hg(2+). The hybrid material can be synthesized by the direct anchoring of Au and Fe3O4 NPs on the functional groups of GO. This approach affords strong chemical attachments between the NPs and GO, allowing this hybrid material to ultrasensitively detect Hg(2+) in aqueous solutions with a detection limit as low as 0.15 nM. In addition, the deposition of Hg(0) on the surface of Au/Fe3O4/GO could be quickly (within 30 min) and efficiently (>99% elimination efficiency) removed by the simple application of an external magnetic field and then Au/Fe3O4/GO could be subsequently reused at least 15 times, with the elimination efficiency remaining high (>96%).

Ultrasensitive, accurate detection and separation of heavy metal ions is very important in environmental monitoring and biological detection. In this paper, a highly sensitive and specific detection method for Cu(2+) based on the fluorescence quenching of a europium(III) hybrid magnetic nanoprobe is presented. This nanoprobe can detect Cu(2+) over a wide pH range (5.0-10.0) with a detection limit as low as 0.1 nM and it can be used for detecting Cu(2+) in living cells. After the magnetic separation, the Cu(2+) concentration decreased to 1.18 ppm, which is less than the US EPA drinking water standard (1.3 ppm), and more than 70% Cu(2+) could be removed when the amount of nanocomposite 1 reached 1 mg.

Low cost, high activity and selectivity, convenient separation, and increased reusability are the main requirements for noble-metal-nanocatalyst-catalyzed reactions. Despite tremendous efforts, developing noble-metal nanocatalysts to meet the above requirements remains a significant challenge. Here we present a general strategy for the preparation of strongly coupled Fe(3)O(4) and palladium nanoparticles (PdNPs) to graphene sheets by employing polyethyleneimine as the coupling linker. Transmission electron microscopic images show that Pd and Fe(3)O(4) nanoparticles are highly dispersed on the graphene surface, and the mean particle size of Pd is around 3 nm. This nanocatalyst exhibits synergistic catalysis by Pd nanoparticles supported on reduced graphene oxide (rGO) and a tertiary amine of polyethyleneimine (Pd/Fe(3)O(4)/PEI/rGO) for the Tsuji-Trost reaction in water and air. For example, the reaction of ethyl acetoacetate with allyl ethyl carbonate afforded the allylated product in more than 99 % isolated yield, and the turnover frequency reached 2200 h(-1). The yield of allylated products was 66 % for Pd/rGO without polyethyleneimine. The catalyst could be readily recycled by a magnet and reused more than 30 times without appreciable loss of activity. In addition, only about 7.5 % of Pd species leached off after 20 cycles, thus rendering this catalyst safer for the environment., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A simple Al(3+) sensor, 8-acetyl-7-hydroxy-4-methylcoumarin (AHMC), was synthesized. It can display an excellent fluorescence "turn-on" response to Al(3+) over other common metal ions in methanol-water media. Theoretical calculations have also been carried out to understand the configuration of the AHMC-Al complex and rationalize experimental absorption data.