Search

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.

Transition metal selenides have gained enormous interest as anodes for sodium ion batteries (SIBs). Nonetheless, their large volume expansion causing poor rate and inferior cycle stability during Na

PDF file 146K, This file contains the legends to Supplementary Figures 1-7 and Supplementary methods

S1 XLSX file 63K, This Supplementary Table contains the results of ORF screen to identify genes that can rescue the suppression of TBK1 in a KRAS-dependent cell line

Autophagy has been shown to be elevated in pancreatic ductal adenocarcinoma (PDAC), and its role in promoting established tumor growth has made it a promising therapeutic target. However, due to limitations of prior mouse models as well as the lack of potent and selective autophagy inhibitors, the ability to fully assess the mechanistic basis of how autophagy supports pancreatic cancer has been limited. To test the feasibility of treating PDAC using autophagy inhibition and further our understanding of the mechanisms of protumor effects of autophagy, we developed a mouse model that allowed the acute and reversible inhibition of autophagy. We observed that autophagy inhibition causes significant tumor regression in an autochthonous mouse model of PDAC. A detailed analysis of these effects indicated that the tumor regression was likely multifactorial, involving both tumor cell–intrinsic and host effects. Thus, our study supports that autophagy inhibition in PDAC may have future utility in the treatment of pancreatic cancer and illustrates the importance of assessing complex biological processes in relevant autochthonous models.Significance: This work demonstrates that autophagy is critical pancreatic tumor maintenance through tumor cell–intrinsic and –extrinsic mechanisms. These results have direct clinical relevance to ongoing clinical trials as well as drug-development initiatives. Cancer Discov; 8(3); 276–87. ©2018 AACR.See related commentary by Noguera-Ortega and Amaravadi, p. 266.This article is highlighted in the In This Issue feature, p. 253

PDF file 1227K, This file contains Supplemental Figures 1-7, which provide additional supporting information for each of the main figures

Supplementary Figure 1. Characterization of inflammatory cell infiltrates and their recovery with time. Supplementary Figure 2. Negative feedback control of pTBK1 by autophagy. Supplementary Figure 3. pTBK1 levels correlate with underlying levels of basal autophagy. Supplementary Figure 4. Lack of total TBK1 enrichment in autophagosomes. Supplementary Figure 5. Screening of autophagy receptors that regulate selective autophagy of pTBK1. Supplementary Figure 6. MRT67307 or CYT387 treatment inhibits pathogen xenophagy. Supplementary Figure 7. CYT387 treatment inhibits IFNγ induced PD-L1 expression in 8988T cells. Supplementary Figure 8. Jurkat T cell recruitment by exogenous CCL5 or 8988TsgATG5 cells.

Supplemental Figures

Autophagy promotes tumor progression downstream of oncogenic KRAS, yet also restrains inflammation and dysplasia through mechanisms that remain incompletely characterized. Understanding the basis of this paradox has important implications for the optimal targeting of autophagy in cancer. Using a mouse model of cerulein-induced pancreatitis, we found that loss of autophagy by deletion of Atg5 enhanced activation of the IκB kinase (IKK)-related kinase TBK1 in vivo, associated with increased neutrophil and T-cell infiltration and PD-L1 upregulation. Consistent with this observation, pharmacologic or genetic inhibition of autophagy in pancreatic ductal adenocarcinoma cells, including suppression of the autophagy receptors NDP52 or p62, prolonged TBK1 activation and increased expression of CCL5, IL6, and several other T-cell and neutrophil chemotactic cytokines in vitro. Defective autophagy also promoted PD-L1 upregulation, which is particularly pronounced downstream of IFNγ signaling and involves JAK pathway activation. Treatment with the TBK1/IKKϵ/JAK inhibitor CYT387 (also known as momelotinib) not only inhibits autophagy, but also suppresses this feedback inflammation and reduces PD-L1 expression, limiting KRAS-driven pancreatic dysplasia. These findings could contribute to the dual role of autophagy in oncogenesis and have important consequences for its therapeutic targeting. Cancer Immunol Res; 4(6); 520–30. ©2016 AACR.

Deep neural networks (DNNs) are getting deeper and larger, making memory become one of the most important bottlenecks during training. Researchers have found that the feature maps generated during DNN training occupy the major portion of memory footprint. To reduce memory demand, they proposed to encode the feature maps in the forward pass and decode them in the backward pass. However, we observe that the execution of encoding and decoding is time-consuming, leading to severe slowdown of the DNN training. To solve this problem, we present an efficient parallel memory compression framework—EPMC, which enables us to simultaneously reduce the memory footprint and the impact of encoding/decoding on DNN training. Our framework employs pipeline parallel optimization and specific-layer parallelism for encoding and decoding to reduce their impact on overall training. It also combines precision reduction with encoding for improving the data compressing ratio. We evaluate EPMC across four state-of-the-art DNNs. Experimental results show that EPMC can reduce the memory footprint during training to 2.3 times on average without accuracy loss. In addition, it can reduce the DNN training time by more than 2.1 times on average compared with the unoptimized encoding/decoding scheme. Moreover, compared with using the common compression scheme Compressed Sparse Row, EPMC can achieve data compression ratio by 2.2 times.

Upconversion (UC) nanocrystal phosphors have received increasing attention for designing optical temperature sensors. Developing an efficient UC phosphor with superior temperature sensing properties remains a challenging task. Herein, we report dual-emitting and thermochromic Mn2+ co-doped KLu2F7:Yb3+/Er3+ nanocrystals, synthesized by a modified hydrothermal method. The marked influence of Mn2+ on the UC luminescence and thermal sensing performances of the KLu2F7:Yb3+/Er3+ nanocrystals was shown. The introduction of Mn2+ into the KLu2F7:Yb3+/Er3+ nanocrystals resulted in a slight change in crystal structure and morphology. The Mn2+ ions were shown to improve the UC emission, which might be attributed to the distortion of the local symmetry. Moreover, the optical temperature sensing properties of the nanocrystals were investigated. Based on the fluorescence intensity ratio of the thermally coupled levels and non-thermally coupled levels corresponding to the Arrhenius equation, the thermal sensing behavior of KLu2F7:Yb3+/Er3+ and KLu2F7:Yb3+/Er3+/Mn2+ was studied in the range of 303–543 K. Compared with the previous study, the KLu2F7:Yb3+/Er3+/Mn2+ nanocrystals exhibited outstanding temperature sensing properties based on non-thermally coupled levels. This study not only discussed the influence of Mn2+ doping on KLu2F7:Yb3+/Er3+ nanocrystals working as nanothermometers, but also provided a general approach to enhance the properties of optical temperature sensors by introducing non-thermally coupled levels.

High catalytic activity and sufficient durability are two unavoidable key indices of an efficient heterogeneous catalyst for the direct carboxylation of terminal alkynes with CO2 conversion. Nitrogen-rich covalent triazine frameworks (CTFs) are promising substrates, while random distribution of some residual –NH2 groups 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 –NH2 groups 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 CO2 adsorption 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 CO2 under 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%. CO2 conversion proceeds well under the synergistic effect between the high CO2 capture 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 development of Ho-based red-emitting upconversion (UC) nanoparticles with small size is of great significance in scientific research and practical application. Besides, a time-saving and environment-friendly strategy for the synthesis of core–multishell UC nanoparticles is urgently needed. In this work, small NaHoF4@NaYF4:Tb@NaGdF4:Yb,Tm@NaYF4 core/shell/shell/shell nanoparticles were successfully prepared by a modified co-precipitation method, in which sequential growth of shells could be realized. By means of Tb3+-mediated interfacial energy transfer (IET) and energy migration (EM), a novel mechanism for Ho-based red UC emission is presented under the premise of a small core size and thin shell. In the system, Ho-based red dominant emission mainly comes from the cross-relaxation process among Ho3+, which is induced by IET from Tb3+ to Ho3+. The EM process among Tb3+ can facilitate efficient energy transport. Furthermore, a mouse experiment demonstrates the deep penetration of 980 nm excitation and Ho-based red dominant emission. This new type of Ho-based red-emitting core–multishell UC nanoparticles not only provides an in-depth understanding of the IET-mediated energy-managing strategy but also displays special advantages in biomedical applications.

In this work, we report a facile strategy to obtain the single-band red upconversion (UC) luminescence of Er3+ by the tunable bandgap of the host. The Er3+/Yb3+ codoped bismuth oxyiodide (BiOI, Bi4O5I2, Bi5O7I) with different bandgap are synthesized via in situ calcination of BiOI. Theoretical and experimental results indicate the bandgap is tuned from 1.86 to 3.13 eV in the calcination process from the original the Bi/I ratio changing. Through the bandgap engineering, the Bi4O5I2:Yb3+/Er3+ exhibits intense single-band red emission, due to its bandgap of 2.39 eV, can effectively absorb the green UC emission to generate e−/h+ pairs under NIR irradiation, which is confirmed by the degradation of RhB under NIR light irradiation. Furthermore, the UC luminescence and NIR photocatalytic activity of Bi4O5I2: Yb3+/Er3+ can be optimized by modulating the doping concentration of the Yb3+. The Bi4O5I2:6%Yb3+/Er3+ exhibits the strongest red emission and the superior photocatalytic performance in degrading BPA under NIR light irradiation. This research suggests an effective way to realizing single-band red emitters by bandgap engineering and demonstrates Er3+/Yb3+ codoped appropriate bandgap bismuth oxyiodide could be potential application in NIR-responsive UC photocatalysts.

Currently, the red-to-UV-blue (R/U) ratio in the existing upconversion (UC) nanophotoswitches is too low to effectively realize real-time monitoring/imaging during the photodynamic therapy (PDT) process. Besides, the imaging depth is quite limited by using the NIR-I excitation (NIR-I = the first near-infrared biological window: 700–1000 nm), which cannot effectively determine the location of cancer cells before the induction of PDT. In this work, a novel NaErF4:0.5%Tm@NaYF4@NaYbF4:0.2%Tm@NaYF4 UC core–multishell nanophotoswitch is presented. For this Nd3+-free nanophotoswitch design, on the premise of ensuring the optimum intensity of UV-blue emission, red UC emission intensity is significantly enhanced under dual-NIR excitations. When the switch is turned off (before the induction of PDT), UV-blue emissions are turned off and red emission is left for real-time imaging under 1532 nm NIR-II excitation (NIR-II = the second near-infrared biological window: 1000–1700 nm), due to which the location of cancer cells can be effectively determined. When the switch is turned on, UV-blue and red emissions are simultaneously turned on with a high R/U ratio for PDT and real-time monitoring/imaging under 980 nm NIR-I excitation. This new type of UC nanophotoswitch can not only realize real-time imaging, but also simultaneously realize PDT and real-time monitoring/imaging, demonstrating the distinct advantages in bioapplications.

In this work, we design oxygen vacancy-rich BiOBr:Yb3+/Er3+ (BYE-OV) ultrathin nanosheets, which can effectively enhance UC luminescence by oxygen vacancy engineering. Density functional theory calculations and UV-Vis-NIR absorption spectra reveal that the existence of oxygen vacancies leads to the formation of an intermediate band (IB) in the bandgap, which can enhance the light absorption ability and promote electron excitation and bandgap transitions (VB → CB, VB → IB and IB → CB), thereby providing the transfer of abundant electrons from the host to Er3+ ions. As a result, the emission intensity of green and red is exceptionally enhanced by 6.5 and 12 times respectively via introduced oxygen vacancies. Meanwhile, BYE-OV exhibits superior photocatalytic activity for the degradation of RhB under visible-NIR light irradiation. The enhanced activity can be mainly ascribed to enhanced photoabsorption in the visible-NIR region and improved UC luminescence. This work offers a new strategy for a rational design for enhancing UC luminescence, which has potential for applications in visible-NIR light photocatalysis.

Graphs are widespread in many real-life practical applications. One of a graph's fundamental and popular researches is investigating the relations between two given vertices. The relationship between nodes in the graph can be measured by the shortest distance. Moreover, the number of paths is also a popular metric to assess the relationship of different nodes. In many location-based services, users make decisions on the basis of both the two metrics. To address this problem, we propose a new hybrid-metric based on the number of paths with a distance constraint for road networks, which are special graphs. Based on it, a most relevant node query on road networks is identified. To handle this problem, we first propose a Shortest-Distance Constrained DFS, which uses the shortest distance to prune unqualified nodes. To further improve query efficiency, we present Batch Query DFS algorithm, which only needs only one DFS search. Our experiments on four real-life road networks demonstrate the performance of the proposed algorithms.

Two-dimensional (2D) semiconductors play an essential role in the field of photocatalytic repairing environment on account of their unique electronic structure and ultra-high specific surface area. Here, a 1-2-layer 2D ultrathin Bi/Bi

Achieving both rapid adsorption rate and high adsorption capacity for bisphenol micropollutants from aquatic systems is critical for efficient adsorbents in water remediation. Here, we elaborately prepared three nitrogen-rich triazine-based porous polymers (NTPs) with similar geometric configurations and nitrogen contents (41.70-44.18 wt%) while tunable BET surface areas and micropore volumes in the range of 454.7-536.3 m

Exploiting near-infrared (NIR) light responsive photocatalysts is especially significant for effective use of solar energy. Enhancing the luminescence of upconversion (UC) photocatalysts is particu...

Lanthanide luminescence nano-thermometers, with great potential applications in photo-thermal therapy for temperature detecting and controlling, have aroused wide interest recently. Enhancing the sensitivity and accuracy of temperature sensing property of those nano-thermometers are of great importance. In the present paper, NaGdF4 upconversion nanoparticles with high doping Bi ions concentration were investigated. With as high as 60% Bi ions doping concentration, no impurity phase was observed in the products and no morphological change occurred. Enhanced upconversion luminescence and thermal sensing properties were obtained, due to the tailoring of crystal field and increasing asymmetry of host matrix. Judd-Ofelt calculation was performed to testify the increasing lattice asymmetry, which was consistent with experimental results. This work provides guidance of tuning thermal-sensing properties of optical nano-thermometer, which are of great significance in bio-sensing field.

Exploring the thermometric properties of UCNPs is of great importance for non-contact fluoresce thermometers. Ln-doped β-NaGdF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs) have been fabricated by varying the ratio of citric ions to molecules in precursor. Morphology of the as-prepared β-NaGdF4:Yb3+,Er3+ UCNPs turns from hexagonal prisms to agglomerations of smaller particles with decreased dimension. Luminescence intensity decreases and red-to-green ratio increases with increasing ratio of citric ions to molecules. A dual-mode thermometric property has been found in the as-prepared β-NaGdF4:Yb3+,Er3+ UCNPs. The first mode derives from the temperature dependent fluoresce-intensity-ratios of thermally coupled manifolds of Er3+ (2H11/2) and (4S3/2) manifolds, of which the maximum relative sensitivity value is 0.0036 K−1. The other mode derives from temperature dependent red-to-green ratios, which is a linear function of temperature and the maximum relative sensitivity value is 0.0238 K−1. The β-NaGdF4:Yb3+,Er3+ UCNPs with morphology of agglomerations of smaller particles with high surface-to-volume ratios show advanced sensitivities, which are suitable for noncontact optical thermometer.

Upconversion nanoparticles, whose thermal sensitivity performances are widely investigated, have attracted great attention recently. Enhancements of their upconversion luminescence and thermal sensing performances are of great importance. In the present paper, upconversion luminescence and lifetime based thermal sensing performance enhancements of NaGdF4 are achieved by a simple solid solution strategy and synthesis environment tuning. With Lu3+ ion doping, Na(Gd/Lu)F4:Yb,Er upconversion nanoparticles of hexagonal phase transformed into those of cubic phase. DFT calculations have been performed, and are in good agreement with experimental results. Higher temperature and lower NaOH contents in the precursor are adopted to prevent the phase transformation from the hexagonal phase to cubic phase. Na(Gd/Lu)F4 solid solutions of a pure hexagonal phase with enhanced luminescence performance are obtained. Both the FIR and lifetime based thermal sensing behavior of the β-Na(Gd/Lu)F4 solid solutions in the temperature range from 250 to 330 K are investigated. Compared with previous reports, β-Na(Gd/Lu)F4 solid solutions exhibit excellent sensitivity properties in terms of lifetime based thermometric properties. This work provides insight into the fabrication of efficient optical temperature probes, which may have a wide range of potential applications in the thermal sensing field.

Upconversion (UC) materials are recognized as promising candidates to harvest solar energy for photocatalysis. In this work, a simple strategy for simultaneously enhancing the UC luminescence and photocatalytic efficiency of BiOBr:Yb3+/Er3+ nanoplates through Fe3+ ion doping is reported. Compared to the Fe3+-free sample, the UC emission intensity was significantly enhanced through tailoring of the crystal symmetry by Fe3+ ions. Experiment and DFT calculations reveal that the introduction of Fe3+ ions resulted in the formation of an impurity energy level, extending to the light absorption region. As expected, the Fe3+-doped BiOBr:Yb3+/Er3+ nanoplates exhibit a wide photoresponse from the UV to NIR regions, good stability, and obviously enhanced photocatalytic activities compared with the BiOBr:Yb3+/Er3+ nanoplates in the degradation of RhB. The boosted photocatalytic activity can be attributed to the synergic effect of the efficient utilization of UC luminescence and Fe3+ doping, where Fe3+ doping could improve the light harvesting capacity, enhance the separation efficiency of electron and hole (e−/h+) pairs, and promote the production of highly oxidative species. This work not only provides a promising system for the efficient utilization of solar light, but also offers a feasible guideline for the further design of broad-spectrum active photocatalysts.

In this work, bifunctional 3D BiOBr:Eu3+ hierarchical nanostructures (HNs) assembled from 2D nanosheets with adjustable thickness were successfully fabricated via a 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 → 7F2 transitions 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.

The Cr and Fe co-doped CeO2 nanoparticles (Ce0.98−xCrxFe0.02O2: where x = 0, 0.01, 0.02, 0.03) were prepared by sol-gel method. Effects of additional Cr dopant on structural, optical and magnetic properties of Fe doped CeO2 nanoparticles have been investigated by X-ray diffraction (XRD), optical absorption spectra, Raman spectroscopy (Raman) and physical property measurement system (PPMS). XRD and Raman studied showed that all samples are single-phase of CeO2 original cubic fluorite crystal structure, Cr can readily be incorporated into the lattice of Fe doped CeO2 and no ferromagnetic secondary phase was found. With the increase of Cr doping concentration, the grain size and crystal quality decreases. The values of optical bandgap energy extracted from the absorption coefficient increase with the increase of Cr doping concentration. The PPMS studied show hysteresis phenomenon, which indicates that the samples have ferromagnetic properties at 300 K. With the increase of Cr content, the saturation magnetization increase obviously. Based on the results of XRD and Raman, it can be concluded that the ferromagnetism is the intrinsic property of the sample.