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Nickel contents of olivine have been widely used as petrogenetic indicators and as fertility indicators for magmatic sulfide potential of mafic-ultramafic intrusions, on the assumption that olivines crystallized from magmas that had equilibrated with sulfide liquid should be relatively depleted in Ni compared with a sulfide-free baseline. This has given rise to a large accumulation of data that is brought together here, along with data on volcanic olivines, to critically evaluate the effectiveness of the approach. We identify multiple sources of variance in Ni content of olivine at a given Fo content, including variability in mantle melt composition due to depth, water content (and possibly source), subsequent fractional crystallization with and without sulfide, recharge and magma mixing, batch equilibration between olivine and sulfide at variable silicate-sulfide ratio (R), and olivine/liquid ratio; and subsequent equilibration during trapped liquid crystallization in orthocumulates. Baselines for Ni in olivine in relation to Fo content are somewhat lower in orogenic belt settings relative to intrusions in continental large igneous provinces (LIPs). This is probably related to differences in initial parent magma compositions, with plume magmas generally forming deeper and at higher temperatures. No clear, universal discrimination is evident in Ni in olivine between ore-bearing, weakly mineralized, and barren intrusions, even when tectonic setting is taken into account. However, sulfide-related signals can be identified at the intrusion scale in many cases. Low-R factor and low-tenor sulfides are associated with low-Ni olivines in several examples, and these cases stand out clearly. Anomalously high-Ni olivines are a feature of some mineralized intrusions, in part due to trapped liquid reaction effects. However, in some cases, this mechanism cannot account for the magnitude of enrichment. In these cases, enrichment may be due to re-entrainment of “primitive” Ni-rich sulfide by a more evolved Fe-rich magma, driving the olivine to become Ni-enriched due to Fe-Ni exchange reaction between sulfide and olivine during transport. An extreme case of this process may account for ultra-Ni enriched olivine at Kevitsa (Finland), but more subtle signals elsewhere could be positive indicators. A lack of clear mineralized/barren distinction in specific groups of related intrusions, e.g., the deposits of NW China or the Kotalahti Belt in Finland, may well be due to “false negatives” where undiscovered mineralization exists in specific intrusions or in their feeder systems, or may also be due to a multiplicity of confounding factors. Wide variability of both Fo and Ni between related intrusions at regional scale may be a useful regional prospectivity indicator, more than an intrusion-scale discriminant, and is certainly informative as a petrogenetic indicator. In general, the use of Ni-olivine as a fertility tool is more likely to generate false negatives than false positives, but both are possible, and the technique should be used as part of a broader weight-of-evidence approach.

The successful use of electrochemiluminescence (ECL) in immunoassay for clinical diagnosis requires development of novel ECL signal probes. Herein, we report lanthanide (Ln) metal–organic frameworks (LMOFs) as ECL signal emitters in the ECL immunoassay. The LMOFs were prepared from precursors containing Eu (III) ions and 5-boronoisophthalic acid (5-bop), which could be utilized to adjust optical properties. Investigations of ECL emission mechanisms revealed that 5-bop was excited with ultraviolet photons to generate a triplet-state, which then triggered Eu (III) ions for red emission. The electron-deficient boric acid decreased the energy-transfer efficiency from the triplet-state of 5-bop to Eu (III) ions; consequently, both were excited with high-efficiency at single excitation. In addition, by progressively tailoring the atomic ratios of Ni/Fe, NiFe composites (Ni/Fe 1:1) were synthesized with more available active sites, enhanced stability, and excellent conductivity. As a result, the self-luminescent europium LMOFs displayed excellent performance characteristics in an ECL immunoassay with a minimum detectable limit of 0.126 pg mL–1, using Cytokeratins21-1 (cyfra21-1) as the target detection model. The probability of false positive/false negative was reduced dramatically by using LMOFs as signal probes. This proposed strategy provides more possibilities for the application of lanthanide metals in analytical chemistry, especially in the detection of other disease markers.

High catalytic activity and sufficient durability are two unavoidable key indices of an efficient heterogeneous catalyst for the direct carboxylation of terminal alkynes with CO2conversion. Nitrogen-rich covalent triazine frameworks (CTFs) are promising substrates, while random distribution of some residual –NH2groups brings challenges to the controlled growth of catalytic species. Here, we adopt a pre-carbonization protocol, annealing below the carbonization temperature, to eliminate the random –NH2groups in CTFs and meanwhile to promote polycondensation degree under the premise of maintaining the pore structure. Benefiting from the improved condensation and orderly N atoms, p-CTF-250, for which CTFs are annealed at 250 °C, exhibits improved CO2adsorption capacity and the ability to control the growth of Ag NPs. Mono-dispersed Ag NPs are generated controllably and entrapped to form Ag@p-CTF-250 catalysts. These Ag@p-CTF-250 catalysts were employed in the direct carboxylation of various terminal alkynes with CO2under mild conditions (50 °C, 1 atm) and showed excellent catalytic activity. In addition, these catalysts have robust recyclability and can be used for at least 5 catalytic runs while retaining yield above 90%. CO2conversion proceeds well under the synergistic effect between the high CO2capture capability and the uniform tiny Ag NPs in Ag@p-CTF-250 “nanoreactors”. The results represent an efficient strategy for controlling the growth of metallic nanoparticles in porous organic polymer substrates containing disordered heteroatoms.

The current small-scale synthesis and relatively large size of Cu2O have limited its practical applications. Herein, we developed a hydrolysis strategy to prepare phase-pure Cu2O networks composed of small granules (ca. 25 nm) on a gram scale. The preparation involves in situ hydrolyzing the Hx[CuxCl2x] complexes prereduced in N,N′-dimethylformamide (DMF). The DMF-soluble Hx[CuxCl2x] complexes are critical for the homogeneous nucleation of CuCl seeds and subsequent hydrolysis, allowing for separate control over the nucleation and growth stages to regulate the formation of Cu2O networks. The novel Cu2O networks possess numerous exposed active sites and hierarchical porosities, conferring high catalytic activity and fast mass transfer capability. The inherent peroxidase-mimic activity of Cu2O is severely inhibited under neutral conditions but can be triggered by Cr6+, enabling the colorimetric assay of Cr6+with the assistance of the oxidation-induced color change of 3,3′,5,5′-tetramethylbenzidine. Through density functional theory calculation, we confirmed that the attachment of Cr6+on the Cu2O surface reduced the dissociation energy of H2O2, enhancing the enzyme-mimic activity. The colorimetric detection method demonstrated a sensitive and specific assay capability for Cr6+(LOD = 0.095 μM). Our work offers a straightforward protocol for novel design of metal or metal-based nanomaterials for nanozymes or other applications.

In this work, bifunctional 3D BiOBr:Eu3+hierarchical nanostructures (HNs) assembled from 2D nanosheets with adjustable thickness were successfully fabricated viaa solvothermal method by altering the amount of sodium citrate. The addition of sodium citrate effectively reduced the thickness of self-assembled nanosheets from 56 nm to 25 nm. The effects of thickness on the photoluminescence (PL) and photocatalytic activities of BiOBr:Eu3+HNs had been systematically investigated. The results showed that the red emission of Eu3+and the photocatalytic efficiency in degradation of MB were both improved significantly as the thickness of the nanosheets decreased. Upon excitation with blue light (465 nm), the BiOBr:Eu3+HNs exhibited intense red emission corresponding to the 5D0→ 7F2transitions of Eu3+ions. Structural insights into the PL of Eu3+ions revealed that the internal electric field (IEF) in BiOBr HNs increased significantly with decreasing sheet thickness, which improved the excitation field of Eu3+ions and favored photogenerated charge separation and transfer. This work not only provided a new thought for understanding the photoreactivity through dopant PL, but also provided a platform for fabricating multifunctional materials for environmental and energy conversion applications.

Luminescence efficiency of trivalent lanthanide-doped upconversion (UC) materials is significantly limited by luminescence concentration quenching. In this work, red UC emission is dramatically enhanced in Er3+-sensitized NaLuF4UC crystals through energy trapping under multiple excitation wavelengths. Cross-relaxation quenching and the energy migration to internal lattice defects are simultaneously suppressed by confining the excitation energy in the Er3+activator after introducing the Tm3+or Ho3+energy trapping center. The enhanced red UC emission (Er3+: 660 nm) mainly comes from the effective excitation energy confinement by Tm3+and Ho3+trapping centers through an easy energy transfer between Er3+and Tm3+/Ho3+: 4I11/2(Er3+) → 3H5(Tm3+) → 4I13/2(Er3+) and 4I11/2(Er3+) → 5I6(Ho3+) → 4I13/2(Er3+). It is found that the confining efficiency of excitation energy in Er3+-sensitized NaLuF4crystals is higher than that in Yb3+/Er3+cosensitized NaLuF4crystals, and the luminescence efficiency of Er3+-sensitized NaLuF4crystals is much higher than that of Er3+-based host sensitization UC crystals (NaErF4). Moreover, Er3+-sensitized UC particles can be efficiently excited by three different wavelengths (808, 980, and 1532 nm), indicating huge advantages for applications in bioimaging, anticounterfeiting, and solar cells.

In this work, self-assembled Yb3+/Er3+-codoped BiOBr 3D flowerlike hierarchical architectures (HAs) were synthesized via hydrothermal method. With increasing pH values, the thickness of samples became thinner, and the morphology transforms from 2D nanosheets to self-assembled 3D HAs. Under the excitation of 980 nm, 3D flowerlike BiOBr:Yb3+/Er3+HAs showed a significant enhancement in the upconversion (UC) emission, which was about 505 times that of the 2D nanosheets. The mechanisms for the enhancement of UC emission have been discussed. Moreover, all the samples showed effective photocatalytic activity for the RhB degradation and obviously enhanced performance with increasing pH values under NIR and simulated solar light irradiation due to the internal electric field effects and efficient utilization of UC emissions. This work gives insight into the guidance of fabricating efficient self-assembled 3D flowerlike BiOBr:Yb3+/Er3+HAs UC materials, which have great potential for the applications in NIR-activated photocatalysts.

An “on-off-on” mode was developed for the detection of mercury ion (Hg2+) and glutathione (GSH) with high sensitivity and selectivity based on the nitrogen-doped carbon dots (N-CDs) fluorescent probe. The N-CDs were synthesized through microwave treatment of citric acid and diethylenetriamine for 2 min, and exhibited excellent fluorescence properties and high quantum yield (27.7%). The fluorescence intensity of the N-CDs could be significantly quenched by Hg2+(turn-off). Upon addition of GSH, the fluorescence intensity of the N-CDs-Hg2+system could be recovered clearly (turn-on). The limit of detection of Hg2+and GSH was 23 and 59 nM, respectively. Moreover, the “on-off-on” probe was successfully applied to the determination of Hg2+in tap water and water from the Yellow River. Meanwhile, due to bright luminescence, good biocompatibility and low cytotoxicity, the N-CDs-based probe was successfully employed as visualizing the intracellular Hg2+and GSH sensors in live HeLa cell.

Energy transfer (ET) is an important route to manage the population density of excited states, giving rise to spectrally tunable emission that is valuable for multicolor imaging and biological tracking. In this paper, a case study of GdF3nanoparticles (NPs) codoped with Yb3+and Er3+was used to experimentally and theoretically investigate the ET mechanisms under near-infrared and violet excitation. Red-to-green ratio (RGR) is used as a primary evaluating protocol, and the power-dependent luminescence and Er3+4I13/2luminescence behavior are used to identify the corresponding conjectures about ET mechanisms. Compared with the four common upconversion (UC) models, a joint effect of energy-back-transfer, multiphonon relaxation, and linear decay depletion mechanisms for the Er3+4I13/2manifold was proposed for the UC process based on UC spectra for samples with different dopant concentrations. Meanwhile, the varying RGR could also be observed from downshifting (DS) emission spectra. The ET mechanism for the DS process, where three cross-relaxation processes coexisted including the Yb3+2F5/2manifold as energy in-transit state, was proposed for the first time. The findings are expected to provide an approach for understanding ET mechanisms in many Yb3+/Er3+codoped UC and DS systems and enable spectrally tunable emission properties for applications that require precisely defined optical transitions.

Incomplete separation and recycling of nanoparticles are causing undesirable nanopollution and thus raising great concerns with regard to nanosafety. Since microorganisms are important regulator of physiological processes in many organisms, the interaction between nanopollution and microbial metabolomics and the resultant impact on the host’s health are important but unclear. To investigate how typical nanopollution perturbs microbial growth and metabolism, Escherichia coli(E. coli) in vitro was treated with six water-dispersible nanomaterials (nanoplastic, nanosilver, nano-TiO2, nano-ZnO, semiconductor quantum dots (QDs), carbon dots (CDs)) at human-/environment-relevant concentration levels. The nanomaterials exhibited type-specific toxic effects on E. coligrowth. Global metabolite profiling was used to characterize metabolic disruption patterns in the model microorganism exposed to different nanopollutants. The percentage of significant metabolites (p< 0.05, VIP > 1) accounted for 6%–38% of the total 293 identified metabolites in each of the nanomaterial-contaminated bacterial groups. Metabolic results also exhibited significant differences between different nanopollutants and dose levels, revealing type-specific and untypical concentration-dependent metabolic responses. Key metabolites responsive to nanopollution exposures were mainly involved in amino acid and purine metabolisms, where 5, 4, and 7 significant metabolic features were included in arginine and proline metabolism, phenylalanine metabolism, and purine metabolism, respectively. In conclusion, this study horizontally compared and demonstrated how typical nanopollution perturbs microbial growth and metabolomics in a type-specific manner, which broadens our understanding of the ecotoxicity of nanopollutants on microorganisms.

Upon stimulation by pathogen-associated inflammatory signals, TANK-binding kinase 1 (TBK1) induces type I interferon expression and modulates nuclear factor κB (NF-κB) signaling. Here, we describe the 2.4 Å-resolution crystal structure of nearly full-length TBK1 in complex with specific inhibitors. The structure reveals a dimeric assembly created by an extensive network of interactions among the kinase, ubiquitin-like, and scaffold/dimerization domains. An intact TBK1 dimer undergoes K63-linked polyubiquitination on lysines 30 and 401, and these modifications are required for TBK1 activity. The ubiquitination sites and dimer contacts are conserved in the close homolog inhibitor of κB kinase ε (IKKε) but not in IKKβ, a canonical IKK that assembles in an unrelated manner. The multidomain architecture of TBK1 provides a structural platform for integrating ubiquitination with kinase activation and IRF3 phosphorylation. The structure of TBK1 will facilitate studies of the atypical IKKs in normal and disease physiology and further the development of more specific inhibitors that may be useful as anticancer or anti-inflammatory agents.

Earlier, we have shown that doxorubicin-loaded liposomes (Doxil) modified with a chimeric phage fusion coat protein specific toward MCF-7 breast cancer cells identified from a phage landscape library demonstrated a significantly enhanced association with target cells and an increased cytotoxicity. Based on some structural similarities between the N-terminus of the phage potein and known fusogenic peptides, we hypothesized that, in addition to the specific targeting, the phage protein may possess endosome-escaping potential and an increased cytotoxicity of drug-loaded phage protein-targeted liposomes may be explained by an advantageous combination of both, cell targeting and endosomal escape of drug-loaded nanocarrier. The use of the fluorescence resonance energy transfer (FRET) technique allowed us to clearly demonstrate the pH-dependent membrane fusion activity of the phage protein. Endosomal escape and cytosolic delivery of phage-liposomes was visualized with fluorescence microscopy. Endosome acidification inhibition by bafilomycin A 1 resulted in decreased cytotoxicity of the phage-Doxil, while the endosome disruption by chloroquine had a negligible effect on efficacy of phage-Doxil, confirming its endosomal escape. Our results demonstrated an endosome-escaping property of the phage protein and provided an insight on mechanism of the enhanced cytotoxicity of phage-Doxil.

Magnesium aluminate spinels were irradiated by electron beams with energy of 1.7 MeV and fluence from 1013to 1017electrons cm-2. After irradiation, the samples were annealed at different temperatures from 100 to 500 °C. Spectroscopic ellipsometry and absorption were used to study the effects of optical properties in the spinel produced by irradiation and subsequent annealing. The results obtained by absorption spectra showed that many F-type absorption centers were produced in the spinels. With increasing electron fluence, we observed an increase in optical absorption, especially in the vicinity of the absorption band at 5.3 eV. The concentration of F-type absorption centers increased as the electron fluence increased. The F-type absorption centers can be destroyed by isochronal annealing. The refractive index obtained by analyzing the ellipsometric spectra changed as the irradiation fluence and subsequent annealing temperature changed. Based on our findings, an attempt has been made to explain the above mentioned phenomena.

Zn1–xMgxO ZMO thin films with x 0, 0.1, 0.2, and 0.3 were prepared on Si100 substrates by the sol–gel method. The influence of Mg content on the structural and the optical properties was studied by Xray diffraction and spectroscopic ellipsometry SE in the UV–visible region. The measured SE spectra were analyzed with an appropriate procedure to accurately determine the thickness and the optical constants of the thin films. It was found that the optical constants of the ZMO films are functions of the film composition. The refractive indices of the ZMO films decrease with increasing Mg content, and the optical bandgap energy exhibits nonlinear behavior or a bowing effect with the change of Mg mole fraction. A maximum band gap of ∼3.91 eV was achieved at x 0.3. © 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim

Single‐phase Ce0.97Co0.03O2films are successfully deposited on Si(100) by radio‐frequency magnetron sputtering. The effects of substrate temperature on the structural and optical properties of Ce0.97Co0.03O2films are investigated. X‐ray diffractometer (XRD) and Raman spectra confirm the formation of the pure CeO2phase with highly (111) preferred orientation for all films. The crystallite size increases with increasing substrate temperature. Atomic force microscope (AFM) images of Ce0.97Co0.03O2films exhibit dense and uniform microstructures with grain sizes of ≈18, 28, and 35 nm for substrate temperatures of 30, 500, and 700 °C, respectively. The surface roughness is increased from 1.49 to 6.72 nm with increase in substrate temperature. Emission at centers of 335, 350, 375, and 392 nm is observed in photoluminescence (PL) spectra. Emission peaks of all films with different substrate temperatures have similar shapes and different intensities. Optical characteristics are studied by spectroscopic ellipsometry (SE) in the UV−NIR region. The optical constants (nand k) are determined by analyzing the SE spectra. The results show that with increase in substrate temperature, the values of nand kincrease, while the value of Egdecreases. The obtained results can serve as a database for the optical properties of Ce0.97Co0.03O2films. Single‐phase Ce0.97Co0.03O2films are successfully deposited on Si(100) substrates by radio‐frequency magnetron sputtering. The effect of substrate temperature on structural and optical properties of Ce0.97Co0.03O2films is investigated. Optical characteristics are studied by spectroscopic ellipsometry in the UV−NIR region. With increase in substrate temperature, the values of nand kincrease, while the value of Egdecreases.

External light stimuli strategy under conventional conditions achieves a sustainable future due to its controllable spatial and temporal precision coupled with environmental friendliness. Herein, atomic Cu(I)-carbon nitride (Cu-CN) was synthesized and served as specific light-stimuli oxidase mimics for total antioxidant capacity (TAC) assay. Singlet oxygen (1O2) and hydroxyl radical (·OH) are the main intermediates, which can oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) into its blue oxidant and therefore improve photothermal signal generation. Based on the intrinsic light responsiveness and photothermal conversion property, we established a colorimetric and photothermal dual-mode sensing platform. The proposed dual-mode assay presented a specific assay of ascorbic acid with LOD of 0.28 μM and 0.15 μM, respectively. This platform was further successfully applied to assess TAC of fruits and beverages. It is believed that the intelligently modulated activity and dual-mode detection function of such atomic enzyme mimics can offer a promising strategy for other analytical assays in high repeatability and reproducibility.

Autophagy is a regulated catabolic process that leads to the lysosomal degradation of damaged proteins, organelles and other macromolecules, with subsequent recycling of bioenergetic intermediates. The role of autophagy in cancer is undoubtedly complex and likely dependent on tumor type and on the cellular and developmental context. While it has been well demonstrated that autophagy may function as a tumor suppressor, there is mounting evidence that autophagy may have pro-tumorigenic roles, e.g., promoting therapeutic resistance as well as survival under stresses such as hypoxia and nutrient deprivation. These two, seemingly disparate functions can be reconciled by a possible temporal role of autophagy during tumor development, initially suppressing tumor initiation yet supporting tumor growth at later stages.

Lead lanthanum zirconate titanate (PLZT) amorphous thin films, whose composition is 5/50/50, have been prepared by the sol-gel technique. The optical transmission property of the thin film was measured in the wavelength range of 200-820 nm. The ellipsometric spectra of the PLZT thin film on a glass substrate were measured in the wavelength range of 200-670 nm, and their optical constant (refractive index nand extinction coefficient k) spectra have been determined. The dispersion of the refractive index is interpreted in terms of a single electric oscillator at 9.64 eV. The direct band energy is found to be 3.67 eV.