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Uniform-assembled lanthanide borate nanocrystals have been synthesized via a facile self-assembly process under hydrothermal conditions. All of the prepared lanthanide borate assemblies exhibit a spindle-like profile despite the fact that they belong to different crystal systems and have different formulas for composition. Each assembly is composed of small nanocrystals that are tightly attached along with their lateral surfaces. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy have been used to characterize the structure and morphology of these samples. The mechanism responsible for the growth and assembly of these lanthanide borate assemblies is also demonstrated. After Eu3+ and/or Tb3+ ions are doped inside these assemblies, strong and multicolor emissions can be realized. Notably, tunable emission and a warm-white color can be achieved in the Eu3+/Tb3+ codoped samples. [ABSTRACT FROM AUTHOR]

A facile and productive method has been developed to synthesize uniform LaF3 nanocrystals with controllable shapes, including polyhedrons, nanorods and nanoplates. By tuning the amount of NaOH and ligands (oleic acid and octadecylamine), we can finely tailor the shapes and sizes of LaF3 nanocrystals. Three prepared LaF3 nanostructures were well characterized, followed by a series of control experiments to propose a mechanism for the shape control. Based on the success in materials synthesis, controlled patterning of LaF3 nanoplates on substrates has also been achieved. After Yb/Er or Yb/Tm was co-doped in these LaF3 nanostructures, they could serve as nanoparticulate host matrices to give strong upconversion luminescence, showing great potential in biomedical applications considering their small sizes and well-defined shapes. [ABSTRACT FROM AUTHOR]

Synthesis of NaYF4nanocrystals with well-defined shapes and/or architectures has been of great interest in recent years, owing to their unique optical properties and wide applications in biological fields. NaYF4nanocrystals with conventional morphologies have been developed through a variety of chemical or physical methods; however, it still remains challenging to build complex architectures by assembly well-defined NaYF4nanocrystals in a simple system. Here, we present a facile solution-based method for synthesizing assembled NaYF4nanocrystals at large scale. These assemblies exhibit a spherical appearance within which NaYF4nanocrystals are tightly attached and arranged along the same crystalline orientation. This interesting hierarchical structure not only offers a high surface area and easy modification surface, but also provides a new efficient host for doping various lanthanide ions to give strong down- or up-conversion emissions. It is anticipated that these unique assembled NaYF4nanostructures will serve as biolabels in various biomedical applications. [ABSTRACT FROM AUTHOR]

Upconversion nanoparticles (UCN) that are excited in the near infrared (NIR) region were synthesized and modified to enable their application to biological systems for imaging. The UCN obtained are oleic acid capped and hence hydrophobic in nature. Since the particles were to be used for imaging cells, a surface modification to make them hydrophilic and biocompatible was performed. Silica coating was chosen for the modification due to the possibility to further functionalize the surface and conjugate biomolecules. Cardiac cells which are capable of forming gap junctions were selected to be labeled. Gap junction specific antibodies were conjugated to the silica-coated UCN. The fluorescence emission spectrum of the particles was obtained with a continuous wave 980 nm laser and size of the particles before and after coating was determined to be 30 and 50 nm, respectively, by TEM. A covalent coupling method was used to bind the gap junction specific antibody to the nanoparticles. The fluorescence imaging experiments were carried out on cardiomyoblast cells and co-culture of bone marrow stem cells/cardiomyoblast cells after incubation with the antibody-modified UCN. Images of the particles after incubation with cardiac cells obtained over days demonstrated the potentials of the UCN for fluorescence imaging. [ABSTRACT FROM AUTHOR]

Despite plenty of reports on the preparation of Au nanorods, it remains challenging to grow uniform Au nanorods with diameters below 5 nm. In this communication, we demonstrate the facile synthesis of ultrathin Au nanorods with a uniform diameter of 2 nm and an average aspect ratio of 30. The synthesis involves the room-temperature aging of a mixture of the [AuCl(oleylamine)] complex with amorphous Fe nanoparticles in chloroform. Analysis of the growth mechanism indicates that Au nanoparticles with a high density of defects were formed at early stages, followed by etching and redeposition process that gradually led to the growth of ultrathin Au nanorods along the ⟨111⟩ direction. This growth mechanism is different from the mechanism recently reported for ultrathin Au nanowires (ref ), where the [AuCl(oleylamine)] complex is assembled into polymer chains followed by reduction to form wires, although the template effect of oleylamine for the formation of ultrathin Au nanorods cannot be completely ruled out. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus (SARS-CoV) is the pathogen of SARS, which caused a global panic in 2003. We describe here the screening of Chinese herbal medicine-based, novel small molecules that bind avidly with the surface spike protein of SARS-CoV and thus can interfere with the entry of the virus to its host cells. We achieved this by using a two-step screening method consisting of frontal affinity chromatog- raphy-mass spectrometry coupled with a viral infection assay based on a human immunodeficiency virus (HIV)-luc/SARS pseudotyped virus. Two small molecules, tetra-O-galloyl-β-n-glucose (TGG) and luteolin, were identified, whose anti-SARS-CoV activities were confirmed by using a wild-type SARS-CoV infection system. TGG exhibits prominent anti-SARS-CoV activity with a 50% effective concentration of 4.5 μM and a selective index of 240.0. The two-step screening method described here yielded several small molecules that can be used for developing new classes of anti-SARS-CoV drugs and is potentially useful for the high-throughput screening of drugs inhibiting the entry of HIV, hepatitis C virus, and other insidious viruses into their host cells. [ABSTRACT FROM AUTHOR]

There are few documented values of the energy levels of the gallium atom. The values in some series remain blank and some series have no values in high Rydberg states. In this paper, based on the weakest bound electron potential model theory we treat the many-valence electron system of the excited gallium atom as a single-electron system of the weakest bound electron and use Martin's expression to determine the parameters. Most of the results are satisfying with deviations less than 1 cm–1 compared with the documented values in the National Institute of Standards and Technology. In addition, we fill many blanks in some high Rydberg energy levels of the gallium atom. PACS Nos.: 31.15.Ct, 32.10.Fn [ABSTRACT FROM AUTHOR]

Investigates the long-chain polymer-assisted growth of one-dimensional zinc oxide nanostructures. Influence factors for the formation of nanostructures; Photoluminescence spectra of the nanowires and nanorods; X-ray photoelectron spectroscopy.

The multi-walled and bamboo-like well-crystalline CNx nanotubes with controllable nitrogen concentration (x = 0.05–1.02) were synthesized, The stoichiometry of as-prepared CNx (x ≅ 1.02) is close to that of the theoretically predicted graphite-like CN. [ABSTRACT FROM AUTHOR]

Surface modification of lanthanide-doped upconversion nanocrystals is crucial to make them useful for various biological applications. Unfortunately, the current methods available to achieve a desirable surface exhibiting both high luminescence and good biocompatibility are limited. In this work, we present a facile microemulsion route to coat carbonized glucose on hydrophobic NaYF4 nanocrystals. Owing to the particular structure of the carbonized shell, glucose coating on these UCNs is not only able to preserve strong fluorescence from the core nanocrystals, but it also confers good water solubility and bears various functional groups for conjugating to biomolecules. Compared to 10 nm silica-coated UCNs, these glucose-coated nanocrystals possess better cell biocompatibility, and can be rapidly internalized into cells. Such unique features of glucose-coated UCNs may find promising applications in imaging, diagnosis and therapeutic purposes. Besides, this facile surface-modification route has the potential to be extended to a broad range of other hydrophobic nanocrystals. [ABSTRACT FROM AUTHOR]

Hexagonal-phase NaYF4:Yb, Er/Tm nanocrystals are the best IR-to-visible upconverting materials to date, but user-friendly methods for making pure hexagonal-phase NaYF4:Yb, Er/Tm nanocrystals with upconversion fluorescence are still lacking. Most of the methods reported so far require excess fluoride reactants in a high-temperature reaction which are very unfriendly to users and raise safety concerns. In this work, an efficient and user-friendly method was developed for the synthesis of uniform hexagonal-phase NaYF4:Yb, Er/Tm nanocrystals with upconversion fluorescence, by forming small solid-state crystal nuclei and further growth and ripening of the nuclei. NaYF4:Yb, Er/Tm nanoplates, nanospheres and nanoellipses were also selectively produced by varying the concentration of the surfactant. All the nanocrystals showed strong upconversion fluorescence, and fluorescence from the nanoplates was observed even when the laser power density was reduced to about 50 mW cm[?]2. These nanocrystals have great potential for use in biology and medicine as fluorescent labels or imaging probes. [ABSTRACT FROM AUTHOR]

Compared to conventional down-conversion fluorescent materials, NIR-to-visible up-conversion fluorescent materials which emit visible light upon near-infrared (NIR) excitation are better suited for biodetection/bioimaging due to their advantages such as minimum photo-damage to living organisms, weak background fluorescence, low signal-to-noise ratio and high detection sensitivity. Uniform hexagonal NaYF4 (b-NaYF4) nanocrystals with up-conversion fluorescence were synthesized. Monodisperse polystyrene nanospheres with an average size of 400 nm in diameter, tagged with different color b-NaYF4 nanocrystals, were prepared using a miniemulsion polymerization method. More than 20 b-NaYF4 nanocrystals were encapsulated in a single polystyrene nanosphere. The nanospheres emit multicolor NIR-to-visible up-conversion fluorescence upon excitation at a wavelength of 980 nm. The nanospheres could be used for a variety of biological applications which require high-sensitivity detection of biomolecules. [ABSTRACT FROM AUTHOR]

Corilagin was seperated from extract of Phyllanthus urinaria L. and used as the precursor of inhibitors of hepatitis C virus (HCV) NS3 serine protease. Six derivatives were obtained through the chemical modification of corilagin and their structures were elucidated by the spectra analysis. Bioassay of these compounds showed that two of them had improved inhibitory efficiency than the pre- cursor, with IC50 values of 2.28 μmol/L and 1.52 μmol/L, respectively. The binding mode of two active compounds with substrate binding site of HCV NS3 protease was also investigated by molecular docking method. [ABSTRACT FROM AUTHOR]

In this Communication, we report the fabrication of well-crystallized rutile-phase TiO2 hollow spheres using potassium titanium oxalate as the precursor. The spheres exhibited unique three-dimensional hierarchical architectures and demonstrated a significantly improved photocatalytic performance. The synthetic strategy used in this process represents a general approach and therefore may contribute to the formation mechanisms of hollow nanostructures. [ABSTRACT FROM AUTHOR]

The climate change characteristics and adaptation abilities of the offshore East China Sea area are very important issues against the backdrop of the Maritime and Polar Silk Roads strategy. Based on meteorological observation data and reanalysis data, the spatial distribution and temporal variation characteristics of sea surface temperature (SST), sea surface salinity (SSS) and winds in the offshore East China Sea area were analyzed. From 1979 to 2017, the offshore average SST increased by 0.18°C/10 a as a whole. The average SSS showed an interdecadal cycle from 1980 to 2017 with a peak in 2005 (34.54 g/kg) and a trough in 1995 (34.26 g/kg). The lowest offshore SSS was 34.0 g/kg in the southern Korean Peninsula and the southern Taiwan Strait, while the highest offshore SSS was 34.8 g/kg in the low-latitude Pacific offshore area. The climatic characteristics annual accumulated gale days, annual local maximum wind speed, absolute maximum wind speed and average wind speed from 1971 to 2017 were analyzed, which showed that the influence of gales on Zhejiang was more serious than their influence on the other provinces in East China. In addition, decision-making strategies for climate change adaptation are discussed to provide a scientific reference for controlling the risks of climate change to the East China coastal zone and the Maritime Silk Road strategy. [ABSTRACT FROM AUTHOR]

This manuscript describes the accurate coating of CdS nanoparticles on the surface of colloidal carbon spheres by a facile two-step, microwave-assisted method and the studies on the photocatalytic activity of the C@CdS core−shell spheres. For the coating of CdS nanoparticles, cadmium ions were incorporated into the hydrophilic shell of colloidal carbon spheres and reacted with an introduced sulfur source under a microwave field to obtain the C@CdS hybrid spheres. Using this process, the as-prepared hybrid structures preserved the good dispersity and uniformity of initial carbon spheres, and the thickness of the CdS nanoparticles shell could be varied or controlled by the irradiation time. A photoluminescence spectrum showed that the C@CdS hybrid spheres feature a broad green emission at around 494 nm (λex= 337 nm). Additionally, CdS nanospheres were successfully prepared in aqueous solution via a microwave-assisted route, and the effect of irradiation time on the products was also investigated. The studies of the photocatalytic property demonstrate that these fabricated functional hybrid structures evinced a higher photocatalytic degradation activity when exposed to visible light irradiation than that of CdS nanospheres under the same conditions. [ABSTRACT FROM AUTHOR]

Three new Lanthanide 2-aminoterephthalate coordination polymers: [Pr2(C8H5NO4)3·(H2O)5]·2H2O 1, [Tb(C8H5NO4)1.5(H2O)2]·2H2O 2 and [Eu(C8H5NO4)1.5(H2O)2]·2H2O 3, were obtained by the hydrothermal synthesis. Crystal data: Complex 1. Triclinic, space group P-1, a=10.391(1), b=15.056(1), c=10.121(1) A˚. α=101.363(4), β=101.115(3), γ=105.737(3)°, Complex 2. Triclinic, space group P-1, a=10.137(1), b=10.353(1), c=9.469(1) A˚. α=95.443(3), β=110.649(4), γ=110.547(4)°. Complex 3. Triclinic, space group P-1, a=10.174(1), b=10.388(1), c=9.480(1) A˚. α=95.443(6), β=110.732(3), γ=110.287(5)°. These carboxyl groups link Ln3+ via the chelating or bridging bond construct one-dimension channels in which pendant function groups can further connect with guest water molecules in channels through hydrogen bond. [Copyright &y& Elsevier]

One-pot hydrothermal process has been developed to synthesize uniform Te@phenol formaldehyde resin core-shell nanowires with unique fluorescent properties. A synergistic soft-hard template mechanism has been proposed to explain the formation of the core-shell nanowires. The Te@phenol formaldehyde resin core-shell nanowires display unique fluorescent properties, which give strong luminescent emission in the blue-violet and green regions with excitation wavelengths of 270 nm and 402 nm, respectively. [ABSTRACT FROM AUTHOR]