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Ammonia inhibition easily affects the performance of anaerobic digestion (AD) for municipal sludge and the oxidization of volatile fatty acids (VFAs) is the rate-limiting step of this process. Bioaugmentation is considered to be an effective method to alleviate ammonia inhibition of AD, but most study used the hydrogenotrophic methanogens as the bioaugmentation culture. In this study, bioaugmentation of mesophilic AD (MAD) and thermophilic AD (TAD) under ammonia inhibition with syntrophic acetate and propionate oxidizing consortia was investigated. The results showed that the bioaugmented reactors recovered earlier than control reactors with 20 (MAD) and 8 (TAD) days, respectively. The high-throughput 16S rRNA gene sequencing indicated that the relative abundance of carbohydrates fermenter (Lentimicrobium), syntrophic VFAs-oxidizing bacteria (Rikenellaceae_DMER64, Smithella and Syntrophobacter) and acetoclastic and hydrogenotrophic methanogens (Methanosaeta, Methanolinea and Methanospirillum) increased in MAD after bioaugmentation. However, part of the bioaugmentation culture could not adapt to the high free ammonia (FAN) concentration in MAD and the effect was weakened. In TAD, proteolytic bacteria (Keratinibaculum and Tepidimicrobium), syntrophic VFAs-oxidizing bacteria (Syntrophomonas) and hydrogenotrophic methanogen (Methanosarcina) were strengthened. The effect of bioaugmentation in TAD was durable even at higher organic loading rate (OLR), due to its positive influence on microbial community. These results suggested that the different bioaugmentation mechanism occurred in MAD and TAD, which are derived from the synergetic effects of ammonia tolerance and microbial interactions. Our study revealed the VFAs-oxidizing consortia as bioaugmented culture could be the potential strategy to alleviate the ammonia stress of AD.

Three 2-phenyl-1,3-diazaazulene derivatives were synthesized and their protonation behaviours were investigated systematically via UV–vis absorption titration and 1H NMR titration, as well as theoretical calculations. One of them exhibited a monoprotonation process while the others displayed prominent halochromic diprotonation responses. Interestingly, upon protonation of 2-phenyl-1,3-diazaazulene derivatives, the coplanarity and conjugation of the 16-π-conjugated backbones were well kept, while the electronic structures were controllably adjusted. The response mechanism of 1,3-diazaazulene derivatives towards acid is through the attachment of acid proton to the nitrogen atom in the diazaazulene ring, resulting in the change of the hybridization of protonated-N from sp2 to sp3, which differed from that of the well-known azulene (analogue of 1,3-diazaazulene, protonation at carbon atom). This work would provide a new insight into the protonation research of the organic functional molecules.

In this paper, a series of Tb 3+ /Dy 3+ /Mn 2+ doped CePO 4 downconversion nanophosphors (DCNPs) were prepared by a one-pot hydrothermal process. The obtained DCNPs presented monoclinic and hexagonal phase structure with wire-like shape. The photoluminescence (PL) properties and the energy transfer (ET) mechanism of these DCNPs were investigated in detail. The ET mechanism of Ce 3+ /Tb 3+ in CePO 4 host was calculated by means of concentration quenching and spectral overlapping, and calculation results revealed that dipole–dipole interactions should be more responsible. The maximum value of ET efficiency was measured to 87.4% for Tb 3+ doped CePO 4 system. In addition, owing to the efficient ET between Ce 3+ and Tb 3+ /Dy 3+ /Mn 2+ , these as-prepared DCNPs exhibit tunable multi-color output under ultra-violet (UV) light excitation. More importantly, the intense cold and warm white emissions can be realized by singly doping 2%Dy 3+ and 20%Mn 2+ in CePO 4 host under UV irradiation, respectively. The corresponding CIE 1931 coordinates were calculated to be (0.30, 0.30) and (0.30, 0.32), respectively, which are closed to the standard white emission (0.33, 0.33). These findings demonstrate the efficient white light emission by singly doped Dy 3+ or Mn 2+ in CePO 4 system for the first time, which is different from commonly used co-doped or tri-doped system. The multicolor tuning and white emission make these Tb 3+ /Dy 3+ /Mn 2+ doped CePO 4 DCNPs potential phosphors in the fields of displays, lighting, and field-emission devices.

In this study, sub-10 nm BaLuF 5 nanocrystals with cubic phase structure were synthesized by a solvothermal method using oleic acid as the stabilizing agent. The as-prepared BaLuF 5 nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and analyzed by the upconversion (UC) spectra. The TEM results reveal that these samples present high uniformity. Compared with Gd-free samples, the size of BaLuF 5 :Yb/Er doped with 10% Gd 3+ decreased to 5.6 nm. In addition, BaLuF 5 :Yb/Tm/Gd upconversion nanoparticles (UCNPs) presented efficient near-infrared (NIR)-NIR UC luminescence. Therefore, it is expected that these ultra-small BaLuF 5 nanocrystals with well-controlled shape, size, and UC emission have potential applications in biomedical imaging fields.

In this paper, the monodispersed NaErF 4 :Yb, Mn nanoparticles (NPs) were successfully synthesized by a simple and mild solvothermal method. The as-prepared NPs were characterized by X-ray diffraction, transmission electron microscopy, and spectrophotometer. The crystal phase, size, morphology, and upconversion (UC) properties of these NPs can be readily tuned by doping Mn 2+ . With increasing Mn 2+ contents, the crystal phase of NaErF 4 :Yb NPs was transferred from hexagonal to cubic, and then a new orthorhombic phase NaMn 3 F 10 appeared. The morphology of NaErF 4 :Yb was tuned from nanodisks to nanocubes and then to large nanoflakes with increasing Mn 2+ dopant contents. Moreover, the UC luminescence (UCL) intensity can be enhanced by increasing Mn 2+ content. Interestingly, single-band red emission can be achieved when the Mn 2+ content reaches 20%. This is mainly ascribed to the efficient energy transfer between Er 3+ and Mn 2+ . The enhanced UCL intensity and single-band red UCL make these NaErF 4 :Yb/Mn NPs ideal probes for optical bioimaging owing to the low tissue absorption and deep tissue penetration of red light.

Visualization of blood vessel of lung can improve the detection of the lung and pulmonary vascular diseases. However, research on visualization of blood vessel of lung using the new generation upconversion nanoprobes is still scarce. Herein, high quality hexagonal phase NaLuF4:Gd/Yb/Er nanorods were synthesized by a simple hydrothermal method through doping Gd(3+). Doping Gd can not only promote the phase transformation from cubic to hexagonal and the shape evolution from microtube to rod-like, but also provide an additional magnetic properties for biomedical application. The as-prepared nanorods were further converted to water solubility by treating with HCl for eliminating the capped oleic acid. The ligand-free nanorods were successfully used for high-contrast upconversion fluorescent bioimaging of HeLa cells. Moreover, the in vivo synergistic upconversion fluorescent and X-ray imaging of nude mice were demonstrated by subcutaneously and intravenously administrated the ligand-free nanorods. The X-ray signals were matched well with the upconversion signal, indicating the successfully synergistic bioimaging. The ex-vivo X-ray and upconversion fluorescent imaging of various organs revealed that the nanorods were mainly accumulated in liver and lung. More importantly, the blood vessel of the lung can be readily visualized when these ligand-free nanorods are intravenously injected. Apart from the synergistic X-ray and upconversion bioimaging, the ligand-free nanorods can also possess excellent paramagnetic property for potential magnetic resonance imaging contrast agent. Our results have demonstrated the enhanced visualization of blood vessel of lung performed by dual-modal bioimaging of X-ray and upconversion fluorescence, revealing the great promise of these nanoprobes in angiography imaging. Such a new technique enables the integration of the two bioimaging techniques by combining their collective strengths and minimizing their shortcomings.

In this paper, the lanthanide (Ln) doped fluorescent/magnetic NaYbF 4 microtubes with hexagonal phase were synthesized via a hydrothermal method using oleic acid as a capping ligand and surface modifier. The as-prepared samples were characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), upconversion luminescence (UCL) spectra, and vibrating sample magnetometer (VSM). The TEM and FE-SEM observations revealed that the NaYbF 4 microtubes present high quality hexagonal prism shape. Under the excitation of a 980 nm laser diode (LD) with a power density of 0.5 W cm −2 , the UCL colors can be tuned from purplish blue to blue, greenish white, and further to yellowish green by adjusting the Tm 3+ and Ho 3+ content in NaYbF 4 system. Moreover, the brighter greenish white light can be readily achieved via increasing excitation power. The UCL mechanisms for the white emission were proposed based on the spectral and pumping power dependence analyses. Moreover, these as-prepared NaYbF 4 microtubes exhibit excellent paramagnetic property at room temperature. The magnetic mass susceptibility and magnetization are measured to 4.17 × 10 −5 emu/gOe and ∼0.84 emu g −1 at 20 kOe, respectively. Therefore, these NaYbF 4 microtubes with hexagonal prism shape, tunable multicolor UCL and excellent paramagnetic property imply that NaYbF 4 is an excellent host material and may find applications in flat-panel displays, lasers photonics and dual-modal bioprobes.

Ultrafiltration, silica gel and chitosan treatment methods were investigated to study the clarification effect on the green tea infusion. The results showed that ultrafiltration reduced the protein and polyphenol content, as well as color of the tea infusion. The silica gel and chitosan treatment were effective methods to clarify green tea infusion; they decreased the haze-active protein significantly, without much effect on the polyphenol. The silica gel and chitosan treatment also reduced the proline content by 18.65% and 23.79%, and histidine amino acid by 90.97%, and 90.31%, respectively. After the silica and chitosan treatment, the protein did not decrease significantly compared to the raw (untreated) infusion, while ultrafiltration treatment reduced the protein content significantly from 11.36 to 5.85 mg/100 mL with the 10 kDa membrane. Transmittance of silica gel and chitosan treated infusion was above 95.0% and 99.0%, respectively; and decreased slowly under prolonged storage time. The chitosan and silica treatment decreased the greenness and yellowness of the green tea infusion.

This paper deals with the heat equation in which the source term involves a Dirac function and describes the elastic reaction of the immersed boundary. We analyze the existence of the approximate solution in two-dimensional case with Dirac function approximated by differentiable function. We obtain the result via finite element method, the Banach Fixed-Point Theorem and a theorem in nonlinear ordinary differential equations in abstract space.

In this paper, we obtain an existence theorem of a connected set of solutions to a nonlinear variational inequality with explicit nonlinear constraints. This result follows in a constructive way by designing a simplicial algorithm. The algorithm operates on a triangulation of the unbounded regions and generates a piecewise linear path of parametrized stationary points. Each point on the path is an approximate solution.

We introduce the problems of differential inclusions for fuzzy maps, and study the existence of solutions to these problems by the continuous selection theorem and fixed point theorems, respectively.